3 problems: Fuel mist from oil line, overheating, and fuel leak re: 1989 v6 150 2.0L

[pjbrownva]

Problem 1) Gas mist coming out of engine from line to pressurize remote oil tank.
Problem 2) Fuel leaking onto powerhead when under load
Problem 3) Engine overheats under load, despite 25 psi shown on water pressure gauge.


I still have 3 issues, on the v6 merc 150 carb that I'm rebuilding.

Help and advice, especially with the first problem would be greatly appreciated.

After the problems, I describe the motor history and the work I've performed thus far.

PROBLEMS
-----
Problem 1: I noticed gasoline mist coming out of the engine side of the hose that pressurizes the remote oil tank. I'm assuming this is not good. What can cause this?

I'm thinking that maybe:

(i) the pressure relief valve on my fuel and oil injection is mis-installed or bad. Anyone with photos on the correct way to install that would help.

I know there's also another pressure relief valve that vents to the atmosphere. Please share a photo on the correct way to install that valve too. I may have it installed incorrectly. or

(ii) Could this be caused by blocked passages inside the engine, such as passages that are internal and somehow related to the bleeder valves that are located on each cylinder? Are there internal passages I need to check and clean? What do I remove to get to them, and what new gaskets do I need to buy and replace before I reassemble those parts?


It appears that this motor sat for 5 to 10 years, and had bugs all inside it, so I don't know if there are more passages that I need to check and clean out, but I assume it's possible that there could be more blockage due to insects and mud or debris from them.


Problem 2: Fuel leaking from somewhere when under load -- I suspect it's the cleanable, reusable in-line fuel filter I installed.

.


I plan to replace it with the disposable in-line kind that is commonly used, and hopefully that will fix the issue. Because it has O-rings to seal it shut, and it can be disassembled, I'm assuming the cleanable filter leaked while under load, and that is the source of my problem. I can and will also replace any suspect fuel lines.


Is 3/8" tubing the standard size for fuel line, and is it OK to use tygon lines?


Problem 3: Overheating under load. The engine overheated while under load. My water pressure gauge showed about 25 psi of water pressure, but the temp gauge quickly went up to 240 F when I put it under load on my test run. When I put the engine in neutral, and let it rev at about 3K RPM, the temp would slowly come back down until the temp was normal again.


Any thoughts on what to check? Could the overheating be caused by the motor running lean due to the fuel leak while under load. If the fuel leak can cause the overheating, then I'll fix the fuel leak before I look into the overheating.


My other thoughts are that maybe I should pull, clean and and check both thermostats, and the poppet valve too.

Do I need to order new gaskets when I pull these parts?

Also, are there any internal passages that I should check? If so what do I pull to see them?

I've never pulled the cylinder head covers. If I take them off, do I need a new head gasket to reinstall?

I have the svc manual and a torque wrench, so I can follow the procedures. Of course, I don't want to pull the head covers, unless it might be helpful.



HISTORY...

This motor is basically a barn find. It had dead bugs all in it (probably a few thousand), and wasps nests in the whole exhaust panel. I had to get spray and kill them all. When I got it, after lubing the cylinders, i had to clean out portions and passages blocked with mud and dirt, probably from the wasps, and clean out the many dead bugs throughout.

I've put on (mostly) used parts, due to cost. (I know, new would be better, but it's not in the cards right now).


Here's a description of the work I've done so far:

1) FUEL PUMP AND LINES
I rebuilt the fuel pump using a kit, and replaced all fuel lines and bleeder hoses.


2) CARBS
I cleaned and rebuilt all carbs with new gasket kits and replaced several needles valves and needle seats, adjusted float levels in bowls so that floats were level when held upside down.


3) IMPELLER FOR WATER PUMP
When I started it up, despite a strong tell-tale stream, the motor quickly over-heated. I shut it down, and doused it with lake water to try to cool the head. I found the culprit was that a prior back yard mechanic had bent the copper piper that carries the water within the lower unit to the head. I replaced the impeller, straightened out the soft copper tube, and reinstalled. I also changed the lower unit oil.

4) UPGRADED TO 40 AMP ELECTRICAL SYSTEM
So, next problem was a weak spark. I ended up replacing the fly wheel, stator, trigger, all six ignition coils, cleaned the plugs, and replaced all six plug wires. In the process, I upgraded from a 16 amp system with a rectifier and 1 voltage regulator, to the newer style 40 amp flywheel and stator with 2 voltage regulators. It took me a while to determine that the 40 amp stator had clearance issues. Using a die grinder, I took off the portions of metal on the top of the engine block that were causing interference. Now it all seems good, and I have a spark on all 6 cylinders, although DVA testing showed a the voltages on the red and red w/ white stator wires are slightly below spec. I don't have the funds to buy a brand new stator this year.

5) ADJUSTED TIMING
I set the throttle stop screw and high speed timing per the manual (I have an old timing light). I also set the low speed timing, and adjusted it on the water in gear to idle at 750 rpm.

6) REPLACED IGNITION SWITCH & BATTERY
Finally, I replaced the ignition switch (it was giving me trouble), replaced the starter motor, put in a new, fully charged battery, cleaned up all of the electrical wiring and batteries cables, and topped off the battery charge before my test run.


RESULT FROM TEST RUN ON THE POTOMAC
The engine accelerated smoothly without hesitation, and it topped out at 5600 RPM, but the speed was low (about 35 mph) when it should have been at 42 - 45 MPH given the prop and experience with other 150's on this boat.


I'm assuming that the fuel leak is at least some of the issue. I know I can find and fix the fuel leak,
but I need help or advice regarding the the gasoline mist coming out of engine into the line to pressurize the remote oil tank.

I also need help regarding the overheating, assuming that a lean burn from a fuel leak won't cause the over heating.

I know I'm getting close, but I really could benefit from expertise available at Scream and Fly.

I'll gladly take and post pictures as I do more work. I know that it makes a thread more interesting.

Sincerely,

-Philip
Arlington, VA

[Merc 2.5]

Well over heating would be a poppit or stats. 25lbs to much pressure and wont draw heat out.of block cause to much flow. If you using oil injection? Get rid.of.it all!

[pjbrownva]

Well over heating would be a poppit or stats. 25lbs to much pressure and wont draw heat out.of block cause to much flow. If you using oil injection? Get rid.of.it all!

Thank you, Merclover.

Do I need to replace any gaskets when I do the work (Must, maybe, not really)?

I ask so that I can order gaskets if they're needed.

I'll fix the fuel leak, and pull, clean and inspect the poppit and the thermostat valves, and report back with the results.


Do you or anyone else also have other suggestions on the fuel mist that came out of the line to pressurize the remote oil tank?. It really seemed like an excessive amount of fuel mist, and if you think the cause is related to the oil injection system, I'll try removing it, at least temporarily...

but because this is a fishing motor, I'd rather keep the oil injection system if possible. Without it, I've found that other motor tens to smoke too much at startup and slow speeds, and foul the plugs.

Of course, if there's an oil I can use that cuts down on smoking and fouling at low speeds, I'm willing to give it a shot.

None-the-less, I prefer the oil injection (when it's working!), and I'm willing to hook up the alarm system to warn me of (at least some types) of failures with the system. So I'd definitely like any suggestions on how to keep it if that seems practical.

(Meanwhile, I'll read the threads here on proper removal and block-off plate for oil injection.)

Anyway, right now I'll find and fix the fuel leak, and pull the poppit valve and tstats.

Do I need new gaskets for the poppit value and tstats? I don't mind ordering them if they're needed.

-Phil

[Merc 2.5]

I would just get poppit kit,comes with everything needed,also the stats have a seal built into them ,no gasket, I've never messed with oil injection unless I was removing it, I have never fouled a plug in my old 2.0 150 but she did smoke,

[Merc 2.5]

Also if u have a mist of fuel or oil or both prob got a dry rot line somewhere b my guess

[tlwjkw]

mix fuel at at least 100 ta one till ya get tha oil injection system workin if that's your target..

the leak... replace both hoses to and from tha main (boat) oil tank.. one from motor to tank pressurizes tank.. one from main tank to motor tank is oil supply.. replace tha one-way valve under tha starter that supplies pressure to tank with a new valve..

over heat.. replace "complete" water pump.. not jus tha impeller.. along with stats, poppet.. you may end up pullin' power head ta check adapter plates for some kinda "varmit" blocking if this stuff doesn't cure tha over heat problem!

when all is right, with or without oil injection, it "should not" foul plugs at any rpm (idle ta wot) for any reason....

[pjbrownva]

mix fuel at at least 100 ta one till ya get tha oil injection system workin if that's your target..

the leak... replace both hoses to and from tha main (boat) oil tank.. one from motor to tank pressurizes tank.. one from main tank to motor tank is oil supply.. replace tha one-way valve under tha starter that supplies pressure to tank with a new valve..

over heat.. replace "complete" water pump.. not jus tha impeller.. along with stats, poppet.. you may end up pullin' power head ta check adapter plates for some kinda "varmit" blocking if this stuff doesn't cure tha over heat problem!

when all is right, with or without oil injection, it "should not" foul plugs at any rpm (idle ta wot) for any reason....

That's great advice.

Question: For Pulling the heads, do you mean remove the plates that hold the spark plugs and cover each cylinder, or do you mean unbolt the whole head from the mid section, and lift it off? (Or do you mean do both?)

Based on your suggestions, I think I'll put in a an oil injection block off plate to temporarily disable the oil injection -- I may even have one around from an old motor... I'll have to check my parts stash. :-)

This way I can make sure the motor is good and will run well on pre-mix before I spend time or money working on the oil injection system.

I'll get a new kit for the poppet valve, and new T-stats too, block of the oil injection, add oil for pre-mix and do another water test.

If I still have overheating issues, then I'll consider a whole new water pump (I did the impeller last year, plus I have a water pressure gauge, so I'm running off of the assumption that if I get 15psi or better under load, that the water pump should be working OK... although that assumes there no blocked passages inside the motor itself -- which might not be true.

Also if u have a mist of fuel or oil or both prob got a dry rot line somewhere b my guess

I'll buy some more fuel line while I'm at it, and replace anything that seems suspect.

Thank you for the advice.. I'll post an update after I've had a chance to get and install some parts.

[tlwjkw]

i'm talkin' 'bout tha "whole power head" to get at tha 2 piece adapter plates/gaskets..

when ya open up tha water pump jus ta replace tha impeller you disturb seated, old gaskets (all of 'em) sooo.. you also can't tell by justa look at tha other parts it they are still in spec or not.. ie: housing, base plate, face plate etc..

once and done!

... justa gauge, will in some cases, not tell tha whole story..

one way ta flush some of tha crud out but not always successful is pull tha gearcase and clamp water hose to tha copper tube.. remove t-stats and turn hose water wide open.. do it with poppet in and again with it removed...…

[pjbrownva]

i'm talkin' 'bout tha "whole power head" to get at tha 2 piece adapter plates/gaskets..

when ya open up tha water pump jus ta replace tha impeller you disturb seated, old gaskets (all of 'em) sooo.. you also can't tell by justa look at tha other parts it they are still in spec or not.. ie: housing, base plate, face plate etc..

once and done!

... justa gauge, will in some cases, not tell tha whole story..

one way ta flush some of tha crud out but not always successful is pull tha gearcase and clamp water hose to tha copper tube.. remove t-stats and turn hose water wide open.. do it with poppet in and again with it removed...…

That makes a lot of sense. I've ordered a full water pump kit, including the base.

Does anyone know what gaskets to order for the exhaust plates, etc. I've tried to look on a few parts sites, and I can't find the info. The serial number is B381657.

[tlwjkw]

http://www.mercruiserparts.com/v-135...-thru-0c100860

http://www.marineengine.com/parts/me...ts/sn/0B381657

[pjbrownva]

http://www.mercruiserparts.com/v-135...-thru-0c100860

http://www.marineengine.com/parts/me...ts/sn/0B381657

puuuurrrfect !!! Your post and others have convinced me to replace many of the existing gaskets, and the whole water pump assembly.

I'll try the water flush trick using a hose on the water inlet tube with the t-stats removed and then again with the poppet valve removed,

but I'm also ordering new parts and new-old-stock quicksilver full gasket set for my motor. This way anything I take apart I can put back

with new gaskets.

With those links, I found a complete quicksilver gasket kit for my motor.

I've also ordered 2 new thermostats and o-rings (But the t-stats were back ordered... so I'll have to try again).

I need to inspect my engine to see if it has the new style or the old style poppet (your link showed both styles) before I get parts to clean
and rebuild the poppet valve.

I also oredered some new smaller hoses, and an oil injection block off kit.

Lastly, NOS genuine quicksilver full gasket set was on ebay for $118 delivered.
It's branded by quick silver, and was manufactured in 2007 in the USA.

So I should be in good shape within about 2 weeks time.(!!!)

I'll post updates and photos when I get the parts and start work.

The gasket kit I ordered comes with the following:
(Based on the description from a sierra equivalent kit)

MERCURY MARINE 27-90484A88
Contains:
( 2 ) 18-0182 Thermostat Gasket, replaced O.E.# 27-62386
( 1 ) 18-0858 O-Ring, replaces O.E.# 254029
( 1 ) 18-0860 O-Ring, replaces O.E.# 25-62700
( 6 ) 18-0129 Reed Block Gasket, replaces O.E.# 27-65744-3
( 2 ) 18-0149 Choke Plate to Carb, Gasket, replaces O.E.# 27-67274-1
( 1 ) 18-0135 Adapter/Meg.Gasket, replaces O.E.# 27-78246
( 2 ) 18-0936 Relief Valve Plate Gasket, replaces O.E.# 27-78690
( 2 ) 18-0952 Relief Valve Plate Gasket, replaces O.E.# 27-88907
( 2 ) 18-7421 O-Ring, replaces O.E.# 25-20415
( 1 ) 18-7411 O-Ring, replaces O.E.# 25-35480
( 1 ) 18-2501 Reed Block Housing Gasket, replaces O.E.# 27-93536-1
( 2 ) 18-2502 Divider Plate Gasket, replaces O.E.# 27-90484-1
( 1 ) 18-2503 Drive Shaft Hsg. to Exhaust Plate Gasket, replaces O.E.# 27-99177-1
( 1 ) 18-2506 Exhaust Plate Gaske, replaces O.E.# 27-99176-3
( 2 ) 18-2508 Exhaust Plate Gasket, replaces O.E.# 27-99776-1
( 3 ) 18-2509 Carb. Mtg. Gasket, replaces O.E.# 27-67751
( 1 ) 18-2510 Reed Block Housing Gasket, replaces O.E.# 27-96761-1
( 1 ) 18-2511 Drive Shaft Housing to Plate Gasket, replaces O.E.# 27-99173-2
( 2 ) 18-2513 Cyl Block Sealing Gasket, replaces O.E.# 27-11338
( 3 ) 18-2803 Carb. Mounting Gasket, replaces O.E.# 27-90430
( 2 ) 18-2808 Cyl. Cover , replaces O.E.# 27-96278
( 2 ) 18-2826 Water Pump Base to Gear Housing Gasket, replaces O.E.# 27-85610-1
( 1 ) 18-2914 Water Pump Gasket, replaces O.E.# 27-85608-1
( 1 ) 18-2915 Water Pump Gasket, replaces O.E. 27-85609-1
( 2 ) 18-3110 Bushin, replaces O.E.# 26-38970
( 1 ) 18-7153 O-Ring, replaces O.E.# 25-25439
( 1 ) 18-7157 O-Ring, replaces O.E.# 25-29976
( 1 ) 18-7159 O-Ring, replaces O.E.# 25-31534
( 1 ) 18-7162 O-Ring, replaces O.E.# 25-33145
( 1 ) 18-7164 O-Ring, replaces O.E.# 25-33466
( 4 ) 18-7168 O-Ring, replaces O.E.# 25-45711
( 1 ) 18-7176 O-Ring, replaces O.E.# 25-90011
( 1 ) 18-7196 O-Ring, replaces O.E.# 25-38099
( 1 ) 18-7812 Fuel Pump Kit, replaces O.E.# 89031A2
( 1 ) 18-7816 Fuel Pump Dia.Kit, replaces O.E.# 21-42990A9
( 2 ) 18-3863 Head Gasket, replaces O.E.# 27-96542-1
( 1 ) 18-0359 Induction Silencer Cover Gasket. replaces O.E.# 27-67275-1
( 3 ) 18-0384 Carburetor Gasket , replaces O.E.# 27-89221-1
( 1 ) 18-2919 Water Pump Gasket, replaces O.E.# 27-42631-1
( 1 ) 18-7406 O-Ring, replaces O.E.# --

[tlwjkw]

does your poppet have two or four mounting bolts?..

[pjbrownva]

does your poppet have two or four mounting bolts?..

I'm not sure. I'll don't have photos, and haven't had an opportunity yet to go to the boat and see,
but I decided to order the kit for four bolts, because almost all of the parts from the 2 bolt kit appear to be included in the 4 bolt kit and the complete gasket set I ordered has poppet valve gaskets for both styles of poppets. Furthermore, the overheating is very likely caused by a problem with the poppet valve, so I wanted to get the parts on their way ASAP -- I sometimes get impatient... just like a kid with broken toy! :-)

I'm also thinking of ordering all new one-way valves that the bleeder hoses attach to. Does that make sense?

After studying several parts diagrams and reading what I could find, it seems like a failure in one or more of those bleeder line one-way valves could be the root cause of the excess fuel and oil I observed spraying from the engine crankcase when I disconnected the hose that pressurizes the remote oil tank.

BTW, if this is normal behavior, someone please clue me in (or test it on your engine if you have a moment). I'd hate to waste time and money trying to fix a problem that really isn't a problem (!!!) It just seemed strange and somehow "wrong" to me -- but that doesn't necessarily mean that it's a problem or even abnormal behavior.

I've already ordered a replacement for the connector on the engine crankcase itself where the remote oil tank pressure hose connects to the block, since the engine diagrams indicate that this connector is itself a one-way valve.

So, does the theory make any sense that a failure in one or more of the five one-way valves that connect to the bleeder line valves is a likely cause of the apparent excess oil and fuel that sprays out of the crankcase ventilation port when I disconnect the remote oil tank pressurization hose from that port?

I don't yet understand enough about how the bleeder hoses and check valves work to determine the answer myself.



I'm referring to the part $30 in the diagram above. My engine takes 5 of them at $10 each.

I've already ordered and plan to install replacements for the following:
#33 Part num 21-42657A3 CHECK VALVE
#35 Part num 21-64871A2 CHECK VALVE

and also a new one-way crankcase ventilation valve -- which is shown as part #40 below:


Even if those parts aren't bad, they're still 30 years old, so the risk of clogging or other failure seems high to me. Why risk it?

I'm also still planning to temporarily remove the oil injection system, install a block off plate instead of the oil injection pump, run 50:1 premix and plug the hose coming off of part #40 in the parts diagram above, just to keep things simpler while I try to get everything else running properly.

I'm getting excited. With the awesome help from Scream N Fly, I think I'll be up and running before I know it!

-Phil

[pjbrownva]

I don't yet understand enough about how the bleeder hoses and check valves work to determine the answer myself.



I'm referring to the part #30 in the diagram above. My engine takes 5 of them at $10 each.

...

-Phil

I (mostly) found the answer, so I thought I'd share what I've learned (in case any others are learning from reading this thread).

I've learned that the purpose of the bleeder lines is remove excess oil and fuel from the intake area near the reed valves behind the carbs, and send it to other parts of engine where it can be used to lubricate parts, or where it can be burned as part of the air and fuel flowing into one or more cylinders.

The one-way check valves make sure that this oil and fuel gets pumped through the bleeder hoses to its destination, rather than just swishing back and forth through the hose.

So, I'm not sure if problems with the bleeder valves could causes the problem I described, BUT the bleeder valves perform a critical function in regards to tasks such as lubricating bearings on the main crank.

Given the age of my engine, and its prior dirty and gummed up state along with the critical importance of these check valves, I decided to just replace all 5 of them (mercury part number 21-426585) with new ones. I found them on Amazon for sale through a third party marine parts dealer for $8.98 each, with free shipping.

So, for $44.90, I'll have peace of mind in knowing that my motor won't blow due to poor lubrication of critical components.
Additionally, problems with those valves is one of at least 1/2 dozen + issues that can cause poor idle, and/or hesitation on acceleration.

So for 45 bucks, I can protect the engine, and not have to worry about these valves as a problem should I experience poor idle or hesitation when accelerating.

Some new parts arrive this week, and I should have the rest by the middle or end of next week.

Stay tuned... they'll be more updates to come.

:-)

-Phil

[pjbrownva]

Here's the latest.

I did some work, tested the engine, and found much better idle, acceleration and top-end performance, but it still overheats under load. Next I plan to replace the whole water pump, and refurbish or replace the copper tube that carries water from the pump to the engine head.

I have two questions:

Q1: When you remove the POPPET VALVE cover: does anything go in second, smaller hole to left of the bigger opening that contains all of the parts for the poppet valve? My engine has nothing inside that second, smaller opening, and I wanted to know if I am missing any parts?

Q2: Can the copper pipe that carries water from the water pump to the engine block be repaired? I noticed that the copper pipe itself is very soft,
and when I first got the engine it was bent by the previous owner who assembled the lower unit incorrectly. I straightened it out, but now consider it suspect. I'm thinking of soldering a new piece of pipe in the middle to make it longer, and then using a pipe cutter on both ends to cut it back down to the proper length, ensuring that it is straight and round on both ends. Of course, maybe it's better to just replace it. I also plan to post in the parts wanted section to see if anyone has a good one for a 20" lower unit to sell.


UPDATE:

I replaced both thermostats and the rubber gaskets that go around them.

I took apart and cleaned the poppet valve -- although I have since received a rebuild kit that I plan to install.

I cut off the broken parts of the hoses going to and from the remote oil tank and reconnected them to the engine and the engine mounted tank.

I replaced the screw on cap for the on-board oil tank.

I replaced the hoses and one-way valves for the oil injection system.

I replaced the fuel lines running from the boat to motor, including the hoes going to and from the manual fuel primer bulb.

I replaced the in-line fuel filter and the hoses going to and from the filter. The hose from the filter to the top carb was and still is a clear
tygon line.

When I took it out for a spin, and I no longer noticed air in the fuel line, which is a good thing.

After adjusting the low-speed timing with the engine running in gear so that it idles at about 600 RPM, the motor now idles well and has smooth acceleration and tops out at 5600 RPM at 42 mph, which is about normal for my rig, but the engine still quickly overheats when under load despite showing 25+ lbs of water pressure.

So next will replace the entire water pump including the base, housing, gaskets, plates, impeller, etc, and I will replace all 5 of the one-way valves that connect to the bleeder hose.

I also plan to replace or repair the copper tube that carries the water from the pump up and into the engine block.
It was previously bent, so I now consider it suspect.

I bought a complete gasket set for the engine, but couldn't get the engine block to break free, or any of the portions of the mid-section.
Despite removing the nuts and bolts, and quite a bit of different efforts to break it free, they were just too stuck. I decided if they were too hard to get apart, that I would leave them together.

So that's the update for now.