2.4 woes again...

[Superdave]

If you responded to my last thread-2.4 won't go over 5000, I got that fixed. Now it idles really rough. It's smooth until it sits a minute. Then it drops off and runs rough for a second then smooths back out. Does it on the hose, but lots worse in the water. I got 0.092 mains w/ 0.094 in #2 & #5. 0.044 idles. Planes off and turns up to 6600 real quick. Could my mains be too large? I tried 0.046 idles and did the same.

[TWright]

It's been a few years for my 2.4 but mine was a Mod VP and it loved .086 jets. It seemed the .090 was too big. Watch your pyrometers if you have them though, they tell you a lot of information. Tom

[us1]

Hey Dave, the gas now a days is way too crappy for any thing under 90. I run my BPs on 92s and 94s. You might look at electrical, usually when a motor loads up it won’t fix its self without being blown out. Is it a Bridge Port or oval? Also check that the floats are not leaking over and pushing gas up the little tubes in the front of the carbs. That will do what you are describing ever time.

[Superdave]

Don't have em. Watched when fuel pump was runnig and did not see fuel running out the tubes. #3 carb was doing that while I was checking the fuel prob I had, adj floats. It doesn't spit out the carb like a reed, but I looked inside and they are all still there. It idles smooth as it can be until it jerks. Maybe like flicking the kill switch off & on faster than light speed LOL. Checked timing and readjusted the linkage, still stutters. It planes off finee and runs great on top. Just this idle makes it hard to shift in & out of gear without killing it. The last 2.4 I had, before it blew, was running 0.082 mains and 0.044 idles. Ran great. Turned my 27 Yamaha 6600 and got real squirrely. I know, it blew. It smoked #3 & #4, but it was because a screw came out of the top of the carb that holds the plate on and leaned it out. It ran for several months. I blue loctited them this time!:confused:

[all8up]

I'd put the 82's back in.

[us1]

What is this thing, a Bridgeport or an Oval? From what you are saying it sounds even more like an electrical problem than before. It is very possible one of the switch boxes is dropping a cylinder at low RPM or it could be a bad coil. Check all the wiring on the coils very closely for a bad connection or loose nut, even the grounds. When it is doing it put a timing light on each cylinder a make sure they are all firing properly.

[us1]

That’s why I am trying to find out if its a stock 200 2.4 or a Bridgeport. If its a stock 200 2.4 the jet are too big but still that will not cause a problem like this at idle.

[Superdave]

Put my timing light on all cyl, ran it in the dark, no sparks jumping. It's an oval with 1.550 exh and chest relieved. When I first start it up, it coughs, but all the reeds are okay, new Boyensens.

[all8up]

Yea I agree, if it is a stocker, it's way fat... and is simply loading up at idle... But I'm not sure what he means by a jerk

[us1]

Definitely leave the jets alone or it will burn up. Now I remember this motor it’s the one with the stock transfers and fingers, right. If you have a good spark on all cylinders while its going on it could only be the carbs. Can you do a DVA test on it? I’m sorry, I talk about so many different motors a day sometimes its hard to remember all of them all the time.

[Superdave]

Finally got my lower unit put back together. Change the mains to 0.082 & 0.084. Went out and ran great, idled good too....until I came back in to the ramp. Came home started on hose. Found primary pickup screw had come loose. Went through the setup again. Still idles smooth & then acts like it misses. Put timong light on all cyl after marking TDC for all 6. It seems #3 & #5 try to crossfire. All the TDC marks are steady until I hook up to #5. It looks likt the #3 mark & the #5 mark are trying to overlap. It stops after a little throttle. I pulled the flywheel and noticed a crack in one of the magnets. Replaced flywheel. Seems slightly better. OHM'ed stator, changed coils, checked groungs. Could the bias circuit be bad in the switchboxes? I removed the idle stabilizer a long time ago. Should I reinstall it? What exactly does it do? Motor ran great WOT. turned up to 6600 before the bow was so high a good wind would finish me LOL. See other post on pad.
Thanks for all your great advise. I WILL FIX IT
Dave

[us1]

Isn't this the motor you raised the Exhaust to 1.500? If it runs good and doesn’t melt on 82s and pump gas you are only making 200 HP.

[Superdave]

I always run 93 octane & extra oil-40:1. Trying not to turn over 6500 until I get the thing to idle. I am going to do more mods when I get this fixed. My plugs are oil soaked after a run wot. While I'm asking... I have a set of pistons that have a square transfer ports and 1/2" fingerport holes. Would it be practical to square the fingerport holes? This motor also has had the transfer port squared at the top ans the fingerports squared and chamfered at the tops.

[us1]

I am worried about the motor, before you do more mods you should find out why its only putting out 200 HP or when you fix it and don't jet up its going to melt. I just built a MOD U oval port 2.4 with the exhaust at 1.500; it runs 96 mains with 100 octane at 297HP.

[Superdave]

If I could get it to idle on the hose without jerking I would install larger jets and put in some more new plugs. The temp gauge only goes to about 3/4 at WOT. I know this has nothing to do with cyl temp. Again I have not pushed it past 6500 yet. It's hard to start the first time, but it's a carb motor so that's okay. It idles real smooth for a couple minutes, then it sounds like it just misse a beat and then picks back up. The motor kinda jerks when this happens, and if it does it more than once, it will die. I can keep it running, by pedaling the throttle. I just felt that since my plugs were oil soaked and black I was too rich. I also have a lot of oily residue coming out the exhaust reliefs when I shut it down on the hose.

[us1]

Something is flooding it at idle. Check that you enrichner valve is not leaking. Disconnect it completely and try to run the motor.

[Superdave]

Sposd to rain for 3 days, then turn cold. Soon as I get a chance.
Thanks John, that's something I havn't checked. I really thought the flywheel thing was the problem.
thanks

[us1]

The black oily fuel running out at idle is flooding for sure.

[Talon2.5]

i gotta say that the jerking it does when it looses a beat sounds electrical and that much residue from fuel on the hose sounds too fat but i wouldnt screw around with jetting till ya get PYROMETERs!!!!!!!!!! with out the pyros jetting is like a blind man shooting pool, youve posted multiple times with this jetting thing and still you have no pyrometers, youve gon from 82's and 90's and back to 82's the main jets have nothing to do with idleing on the 2.4 merc carbs, the idle jet takes care of idleing and the tubes take care of the changover from idle to main jets, you really need some pyrometers to find out the exhaust temp to get the jetting in the ball park and do the plug reading thing from there, poor john is repeating himself over and over on this one, ive seen him ask time and time again "is this an oval port or a bridgeport":D get some pyrometers so your not shooting pool in the dark ;)


my modified 2.4 ran 80's and 82's with 1200 on the pyrometers and the timing at 27 degrees and the throttle linkage changed to give timing before the butterflies even cracked but to get the jets figured out i installed dual pyrometers

skip

[Superdave]

I wasn't trying to piss anybody off, just having a conversation with John. Not everybody has a spare $300.00 to spend. I have kids in college. It's an oval port. John remembers it due to the exh port height. The reason for changing the mains was due to black, oil soaked plugs. I have what appears to be raw fuel/oil running out my exhaust. Apparently I didn't get John too upset, he kept replying this morning. I appreciate EVERYONE's help and hope I can contribute something at some time even with my infintesimally small brain.

[all8up]

Try some 54, or 56 idle jets.. I have been running them for years, with good success.. Also, I do not think you need over 80's for main jets!

[Talon2.5]

you didnt piss anyone off!!!!

i just was commenting on how many times ive seen him and this jetting thing go around

no malice intended, no loud talking meant by my post!!

just a clean cut way of getting past your problem thats all i was trying to say, i went through it too and the pyros helped imensly actually was in the dark without 'em and they are cheaper than frying it

i'm attaching an idle and off idle circuit jpeg that may help ya to get to know the carbs better


skip

[Talon2.5]

if you notice in the idle drawing the jet has zero fuel going through it, now if it's clogged you'll get raw fuel with no air mixture and if theres a problem with the idle tube youl get excess fuel at an idle, i forget what idle air jets i ran but the main fuel jets were 80's and 82's, and when your full out the idle, off idle, and highspeed circuits are all working at the same time, i have the high speed and backdraft circuits to if ya want me to scan and post 'em no sweat, dont be thinking ya pissed someone off 'cause you didnt! after re-reading my post without thinking about what i was trying to say i guess it could be misconstrued but it was never meant like that!

hope the drawing helps

skip

[Superdave]

Thanks for the pic and yes I would like the high speed pic also. Your post started out fine,but maybe I took it the wrong way.So to catch you up. I broke a clutch and clutch dogs on fwd gear and spent some time finding gears. Just got back on the water yesterday and ran again. I ran it on the hose for a good 30min after installing lu & going throught the linkage. Idled great! Even after I got to the lake it idled great for the first 2 runs to fishing holes. Ran back to the ramp and it wouldn't idle. Got home found primary pickup screw had loosened. Readjusted several times with no luck. Like i told John, I felt sure it was the cracked magnet in the flywheel. Put on another with maybe a teeny tiny improvement. I marked TDC on the flywheel for all 6 cyl and used a timing loght to look at them firing. They all line up perfect, but when I hook up to #5 the marks for #3 & #5 seem to overlap. Even with a slight carb opening the motor will still act up. But then sometimes it's smoooooth.

[Talon2.5]

so if 3 & 5 are overlapping that sounds like a switchbox to me because those are the "distributor" on an out board, when it shakes and misses a beat is electrical to me anyway and if it were mine i would go after the switchbox for the starboard side

the raw fuel could be as easy as a sticky float and what john said which i thought was great, the enrichener

i'm attaching the high speed one for ya too

[Talon2.5]

the magnet as you probably know has a noth and south pole in it, it has one factory split line in it, if it has a crack other than that it will have 2 north and south poles, as a result of the two poles the motor doesnt know what to do and the result of that is usually idles and revs good but when ya put it in the water and put it in gear it will die every time, you cant even hardly feather it out of the basin, and in that condition when you remove the exhaust cover you will find one of the banks washed down with fuel do to no spark, i had the irritating chance to find this out first hand, and using a compass around the magnet found the two poles instead of just one, changed the flywheel and BAM she ran great


just an FYI fer ya

skip

[dan agnew]

next time you have it on the hose pull the carb shroud let it idle until skip starts, first is it a skip or is it a sneeze? you should be able to tell a sneeze with carb cover off. if it sneezes you may be able to see the cylinder spit at you if not stick your finger in carb throat one venturi at a time if lean sneeze the offending cylinder will pick up. make sure that carb sync is correct i have found about 90 % of low speed is in one carb butterflys cracked open which upsets balance just cut phillips screws loose at carb link
plastic linkage make sure large pickup on center is not being moved by timing arm. that may solve mystery skip/sneeze/miss

Danny

[Steve Pope]

why not get a pair of known good switch boxs and fit them to the engine once you get this miss to happen predictably. this should eliminate switch box doubts. also, if replacing switch boxs, REPLACE BOTH!!!

[Talon2.5]

hey superdave what happened? you figure it out yet? been a few days now havent seen an update


skip

[Superdave]

I live in TH. It has rained for 3 days. We have flash flood warnings. It rained over a foot in west TN and around 8" in Nashville. I changed BOTH switchboxes and it seemed to idle better on the hose. I also changed the idle jets, it had 0.044's in it. I had some 0.048's and put them in. Waiting on a chance to get out. Will update ASAP.
DAve;)

[Talon2.5]

ok we will wait for your report


till then, skip

[Superdave]

Got a break in the rain. Went out, fired right up. Idled beautifully! Idled out past the no-wake and put her down. Would only get to 1800 rpms. Thought it foled a plug idling so I put it in neutral and held it at 1500 or so and noticed it smoothed out. Put in gear and hit it. 1800. Wouldn't even plane off. Water was rough an rolling so I came home. Tomorrows another day..

[Talon2.5]

ok that exact thing happened to me and it was the carb leaking down, i fixed it and she ran great but did just what your saying and you also were talking about that raw fuel pouring out of the lower unit right? tear em down and inspect them, dont touch the electronics right now because from the sounds of it the skip/miss/jerking is gone right?

so it's time for the carb teardown leave the rest alone for now, tear them down completely and go through every orifice with a blow gun to clear any obstructions and set the float hieghts dont worry about any jetting at this point leave what ya got right now, you will probably find some thing from the carb teardown and rebuilding

skip

[all8up]

sounds like the high speed on the stator is out. replace the stator!

[Talon2.5]

all8up thats what i thought on mine but the high side kicks in around 3800-4000 if i remember right, anyway i changed my stator, trigger, switchboxes and coils and flywheel one at a time and went back and forth the lake on each change and it turned out to be carbs, this was on the 2.5 carb mtor i blew up shortly after going threw that hastle


skip

[Superdave]

The carbs were just gone through, but I am using an elec pump. My gauge broke so the pressure may be too high. Will check ASAP. It has a new stator, 3 months old. Skip, the jerk seems to be gone. Checking carbs for leaking out front metering tubes. Man this can get frustrating. Hey Skip, you don't have any PYROMETERS for sale do you? I'll trade you a bottle of PROZAC. LOL

[all8up]

still sounds like stator to me. The High side should kick in around 1800-2000 rpms. If it were a bad carb it should still plane out, and run on 5 cylinders. Just because it's only 3 months old, it could still be bad. just a thought, I could be wrong. If all else fails, try it. It might save you some grief.

[us1]

The timming light will tell all.

[[email protected]]

Hi there,

May or may not apply, but worth reading anyway. Attached is a Merc Service Bulliten in .pdf format. It is zipped so you will have to have WinZip or something to unzip it. You will Adobe Reader to view it. If you don't have them you can download them at www.winzip.com and www.adobe.com.

GoodLuck,
LS

[Superdave]

I hooked up the timing light and checked all cyl. #5 was still eratic, but idleing good. I swapped the switchboxes front to back etc. #5 still fired erratic. Removed the NEW coil on #5 and ohmed it from stud to high voltage out. Ohmed1300 ohms. Went and got the one I removed and it ohmed the same. The book says 900 or so. I got an old coil I had on a shelf and it ohmed according to the manual. Put this USED one on and #5 stopped jumping and I gained 200rpm at idle on the hose. Going out tomorrow if I can and will let you know.
Thanks for the help. I should have ohmed the old one out when I took it off. I can't return the NEW coil because its an electrical part.
Now SKIP, SKIP--Do you have any PYROMETERS!. Still willing to trade PROZAC LOL.
Now if it's okay I will then get into the jetting thing. Thanks John. The timing light was definitly a big help.
Dave

[Talon2.5]

all8up, when my carb was flooding it would not plane out, believe me i wish i had found that before making trip after trip back to the dock and changing all that electronics, my stsator went out on me once and i was so sure that it went again i paid no attention to the carbs and that was a piss poor decision/troubleshooting on my part and the really bad part is i know better than to get tunnell vision but i did it anyway, stupid me

dave ive got the pyrometer head/guage still but when my 2.4 got stolen (which i was in the process of jetting) they cut the pyro leads and i havent replaced them yet, if i had a spare i would send it to ya!!!

all8up is right a new stator can be/go bad also, but you had heavy fuel problems so i think ya got more to do there and if the electric pump is pushing over 7 pounds ya could be blowing past the needle and seats

my buddy had the same idle and planning problem with a 2.4 and his TPI went south and was too rich his first thought was the stator, he called from a cell phone on the lake and explained what it was doing and i had him check for blockage on the ECU lines and they were clear, i told him the internal tpi he had was going bad and he tried a new ecu and it was fine, sometimes it will seem elecrical when it's actually fuel related, trouble shooting is an art and ya gotta be open minded to looking at all possabilities, i think john and gregg moss are about the best at this on these boards, they know thier stuff!!!

[Superdave]

You want to sell your gauge? I can buy new senders can't I? [email protected]

[Rickracer]

I can get you those pyros. :cool:

[Talon2.5]

not selling the guage i'm getting new leads through rick when i'm done with wifes car


skip

[Superdave]

Here we go. Went out. Idles perfect. Tried 28' chopper II. Went to 3000 and would not plane. Something pickedup, like a miss. Planed off turned 7000 before I blew out. Got a new stator ordered. Rebuilding carbs while I wait. When I went out the day before it was slow coming up, normal for a relieved exh. Got up ran great. Turned a 23 Laser II 6600. GPS at a whopping 52mph!!! Must have LOTS of slip. I can turn a 27 Yammie 6600, but I forgot my GPS. Why such a differnce in the propsize ver rpm??. Update after stator & carbs.
I also noticed the Chopper had a LOT of torque in the wheel. The Laser has zero. After the chopper planed off the boat the boat seemed to flounder until I trimmed it way too far.

[Liqui-Fly]

Dave I went throught the same crap you seem to be going through. Don't start buying lots o chit. Electrical trouble shhoting itself is just an indicator. I replaced everything just to get back to fuel. Now are you running your mechanical pump also or just off the electric? Funny thing is too much fuel acts just like not enough. Everyone will tell you stator, then trigger, then boxes. Make sure your fuel is perfect first. If you got spark on the timing light then you got spark. Don't try to quantify light intensity ect. You'll drive yourself nuts. I had coils fail ohm tests and everything else but once I disconnected my oil injection and stopped running my Holley into the mechanical pump the motor was fine. I took all the old electronics that I was sure were bad and put them back on....guess what....the motor still ran fine. Breath and keep a notebook!!
David

[Talon2.5]

to me, and i'm no guru it sounds like fuel, if it were the stator it would not go to 7000 it would die every time, well there is the possability of heating and loosing contact in the stator type **** but it sounds "fuelish" to me

[us1]

Quite "fuelish"

[Superdave]

I have the elec pump going through filter (WIX) into the reg and to the carb. Reg set at 5psi. I checked pump flow and it's oksy. I put the gauge on the hose after the filter and it only pumps 6.5psi without the reg. Clean ing carbs and reindtalling. I found a used stator at a local dealer. Will try the carbs first.

[Talon2.5]

well that fuel pressure sounds fine, whatever became of the enrichener? did ya leave it hooked up to the top carb and disconect it from the center carb to see if it was dripping fuel into the bottom two carbs?

man if that stator is bad i will be suprised and Wrong to boot

[all8up]

I agree with talon... If your turnin 7 grand it aint the stator. Have you checked the float level? sounds to me like you may have 2 seperate problems..
1) You have a problem with your holeshot, planing off
2) you are disapointed with your lack of rpm's

If the motor is turnin a 28 7000 rpm's, with moderate slip, that's around 90mph, and that aint all that bad, for a mostly stock 2.4. maybe if you could describe the problem better, we could be of more help. i would also avoid using any through hub prop, as it would have a tendency to bog any good runnin high perf motor.

[Superdave]

Been working 7 days 12 hours at work. USPS, Xmas. I have rebuilt the carbs and checked all the reeds while I had the intake off. Will install asap and update everyone. I saw my thread hit page "2"! Turning a little chilly finally. It was 75* most of theast two weeks.
Thanks to everyone
Dave

[Superdave]

Here we go. Put on the carbs and pressurized. No leaks. Went through linkage. Started motor, sounded real funny!!! Put on the timing light. No spark on #2 & #5. Swapped switchboxes front to back. Now no spark on #1 & #6. Took the new boxes back to the dealer and raised enough heel they swapped for 2 more new ones. Will install asap and report back. IMAGINE THAT
IMAGINE THAT!

[DaveR]

Went through this once a long time ago. Thought something was frying good switch boxes. GROUND, GROUND, and GROUND them again. I even ran a seperate wire to the battery just to make sure. Changed both boxes at the same time and the problem went away. I wish you much luck - I feel your frustration!

[Talon2.5]

now thwt you may ahve that bug out of it we need to see if you still have that fuel duming out on the hose you spoke of

[us1]

Hey Skip, how many 6 packs did you have for lunch.:D :D :D

[Talon2.5]

:D boy i sure messed that typing up didnt i!!!!(4):eek:

[Superdave]

Finally.. I have fire on all cyl and it is steady with a timing light. Started on the hose and the amount of raw fuel out the exh is minimal. Sounded good, idled good. I also found the link between the throttle arm and the carb cam was unscrewed a couple of turns. Fixed that and readjusted. Rain started. Will go to the lake when it stops. Bout to run out of energy working too many hours, but it will stop the weekend before Xmas. Hope I don't have to wait that long to test though. Still strokin'

[us1]

This is the longest boat repair thread in history.:D I hope it works.

[Superdave]

Probably cause I been workin & it's been raining. I like setting records anyway. LOL
Who'd a thunk it?

[Talon2.5]

hang in there dave!!! it's worth the effort

[Superdave]

Went out. Idles fine, planed off slow (exh opened)normal, broke over and stayed at 3500 till I trimmed it. Ran right on up. Water was very rough & wind a blowin. Made few passes and trimmed on up, when I get over 6000rpms it falls off. When I push in the enrichener it dies. Anyway did a 5600 shut off and came home. Plugs looked a little dry. Checked comp. 120 on all, but #3 it is 110. I pulled the head and noticed the crosshatch was still quite evident in #3 and not #1 or #5 although there was some. I'm assuming #3's rings haven't quite sealed. US1, Talon,I have 82's & 84 jets in w 46 idles. I'm going to jet up and get a new regulator/gauge. I was running without the reg. 6.5 psi. Glass filter appeared to be full at all times. It is mounted where I can look back at it.

[Talon2.5]

waiting to hear on the bigger jets

[Rickracer]

...but I'd be afraid of having gasoline under pressure in a glass anything. I had a customer years ago that wanted a glass fuel filter installed on the stout street small block I built and installed for him. I refused to put it on, so he did it himself after picking the car up. 3 weeks later, I was re-wiring a goodly portion of the engine wiring harness, and replacing a buch of hose burnt in the fire that resulted from the glass breaking, and dumping fuel all over the manifold. I had to tell him, "I TOLD YA SO". We replaced it with a Wix 33033.

[Superdave]

I think we should close this thread. I have "FIRE". I will change jets and waiting on a reg & gauge. John, I believe your were correct in that I was lean. All this other crap happened and I got sidetracked. Thanks to everyone for their thoughts & suggestions. Just to clear it all up. I had a bad swotchbox. Bought 2 NEW ones that apparently were bad. Yes, I had ALL the grounds hooked up before I cranked it. BOTH NEW boxes were bad. One had no fire from the top cyl, the other no fire from the bottom. Finally talked them into exchanging them at the place I bought them. Now I'm loosing rpm over 6000. Plugs look lean. Will post after I get it all fixed and tested. Raining again.
Thanks again, esp John, Skip
Dave