View Full Version : Problems during break in 260
As some of you may remember I stripped the splines in my 260 crank when my lower unit came loose seven weeks ago. Since I had to replace the crank I simply decided to go through the entire motor even though it was running like a million bucks. I sent the block to John Marles for his porting, had him top pin the pistons, put in a set of light weight wrist pins and replaced the rings.
I finally got it put back together and was able to put it in the water yesterday to start the break in process. The last time I had the boat in the water when my lower unit came loose I had just put in new injectors and PCU from Tony and Linda Brucato. The boat was running unbelievable. I was very happy with it. The only thing I changed on the motor set up was in the PCU. I turned up the overall fuel curve by 8% for the break in. Of course now the block is ported. But, that shouldn't be causing my problem.
When I dropped the boat in the water it started right up. I ran it for a while on the trailer. Let it cool down. Then I took it off the trailer and on the lake. The power seems real lazy. I've never felt it so lazy as a matter of fact. It struggled to get on plane. Once on plane I was crusing about 3000-3500 RPM's just trying to run some heat through the motor. All the gauges looked good. Never saw more that 900 on both EGT's. I decided to give it some throttle to see how it would respond and I couldn't get he motor over 4700 RPM's. When I would give it gas I could hear the motor sucking in more air which generated more noise. But, the motor would not generate more RPM's, power or speed. The motor wasn't cutting out, just wouldn't build any more than 4700 RPM and was very lazy on up to that point.
The motor idles fine and start up fine. I must be over looking something. Not sure what and would appreciate any suggestions. Like I said before, it ran perfect last trip out before I stripped the splines in the crank. When the motor came apart the pistons still looked new, the cylinder walls looked perfect as well. The motor has never stuck, no sleves, no failures what so ever. Just prior to my trip when the boat was running so well I purchased a new motor harness, new injectors from Tony, had them flowed and calibrated, new PCU from Tony with one of his curves, new fuel line, new fuel filters, new air sensor, new plugs, 31cc heads from Ruck and the boat ran great. The battery was fully charged. Besides, I run a Simon Alterntor kit. So, plenty of volts. I don't know. I didn't change the timing. Never broke the lock nuts loose on the adjustment.
One thing that did happen is the flywheel could have rotated perhaps one set of holes to the right or left. I'm not making myself clear. Let me try again. In order to install the pulling ring on my motor I had to remove the Simon pully on the flywheel. In order to do that I had to take the 8 bolts out of the top of the flywheel. Then I was able to thread in the pulling ring in the top of the motor and lift my motor off the boat. Well I forgot to put any of the 8 bolts back in the flywheel. I didn't notice this until a few days later when a saw the flywheel off center and loose. I then rotated it to the closest set of holes and put a few bolts in it to keep it aligned until I was ready to put the motor back on the boat. It is possible that the flywheel isn't in the same possition in relationship to the 8 holes that bolt in down. I don't know if this even matters to be honest. I just thought I would throw that out there so you know all the facts. If the flywheel has to be in one specific position in relationship to the 8 bolt holes, how do verify that it is in the correct position? And, could this be causing my problem? Thanks for any help
STVmod
08-28-2006, 12:57 PM
Check the timiing, that woud be a good place to start.
--mirage1--
08-28-2006, 03:46 PM
Buy a dial indicator and a manual.
The Big Al
08-28-2006, 04:17 PM
Plus 8% could be the problem.
At idle the extra fuel is not that noticeable.
But during take off it is.
I have the PCU and feel you should go back to even and see what happens.
I believe in double oil, but not extra fuel during break-in.
STVmod
08-28-2006, 04:18 PM
yes i should of mentioned that you will need to indicate the cylinders before you check the timing?
Well, I'll be checking the compression and double check that each hole is getting spark tonight after work. I'm sure it will be fine. But, I'll still check it. I never thought the 8% would make that big of a deal. I'll put it back down 8% to check it out. That would be an easy fix. I was under the impression that with the new exhaust chest work the motor would need more fuel. I can check to see if the timing has changed since I split the cases. I just left it where it was before since it was running so well. Couldn't hurt to check it. Thanks for the help.
Jay Smith
08-28-2006, 05:48 PM
Some say that it doesn't matter where the flywheel is attached to the hub , but I have heard from different people that it does. I ALWAYS set up a flywheel so that the woodriff key way on the hub is pointing directly to a magnet that ATTRACTS another magnet. There are 12 magnets on the charging ring of a 2.5 Mercury fllywheel ( 6 north magnets and 6 south ones ) If you check the magnets with anothet magnet you will find 6 that attract and 6 that repell. Also there is a magnetic ring fitted on the OD of the hub with 2 magnets they repell a magnetic piece of metal 180 degrees apart from one another , this is where the firing ignition trigger takes it signal from and relays that information to the switch boxes telling the coils when to fire in proper sequence you can use a feeler gauge to check the 180 degree apart condition rubbing a .020" feeler gauge in a motion like your shaving the hubs shiny chrome surface and check the matching strengths of both magnets they BOTH will repell the feeler gauge if one is alot weaker that the other the hub is bad and the motor will not run correctly.
Also you might try a plug change, me being in the motor building business I find SOOO many guys that loose track that ALL that assyembly grease and extra oil is now being brought up to the plugs with the fuel vapor and the start up plugs are now a VERY good canidate for fouling. I START a motor off with the BUHW the cheapest plug for a Merc and allow those to foul instead of a $7.50 a piece high $$ plug. After an hour on the hose I instruct the customer to replace with the correct plug and heat range for thier application. 8% is pretty big jump also I might try 3%... To break in it would be difficult even at 0% to burn one up 4000 and below.
Dunno but those are things I'd look at first !
Good luck,
Jay
Thanks Jay, I didn't even think of the assembly lubes fouling plugs. The plugs are brand new when I lit it off. I guess you live and learn. I would have put a cheap set in for the first hour if I new that. I suppose I can buy a new set and see if that helps. I'll keep you posted. Thanks
Just got done checking the basics on the motor. First I checked the timing and it seems fine. The trigger is moving Ok as well. I can say that it's running extremely rich based on the build up on the lower unit and the prop. So, I then did a compression check and I am sad to say that on #1 I have no compression. My gauge starts at 30 PSI and it doesn't even register. All other's have 150 across the board. I don't know what could be causing this. It makes no sense to me. Very unhappy about this. To think the motor was running like a million bucks before the lower unit came loose and screwed up the splines in the crank. When the motor came apart the pistons looked new. Just to be safe I installed new rings and top pinned the pistons. No big deal. So, I just don't know. It's like there is no piston in the hole. I put the dial indicator in the hole and there is most definetly a piston in the hole. I was to pissed off to pull the head. I'll do it in the morning. Not sure what I can see with the head off. I won't be able to tell if one of the new rings is stuck. I would imagine that even if the rings were stuck I would have around 50-60 PSI. I hope the assembler put the rings on that piston. I'm sure he would have noticed having an extra two rings if he forgot to install them. To add to my problems, even with the one hole dead it should have ran better than it did and not so rich. First things first. Anyone have any ideas? Thanks again.
RB in NM
08-31-2006, 04:48 PM
Ouch !
This ain't likey headin' for a happy ending by the sounds of things. Need to pull them heads and have a check asap.
Sucks to hear of yer problem. Hope the best fer ya !
Russ
The Big Al
08-31-2006, 04:57 PM
Have you pulled the head yet?
He pulled the heads. I saw the pictures. It detonated on the exhaust port with little cylinder damage. Al, he needed the extra fuel for the port work not the break-in. RC51, post the pictures so you can get more opinions.
The Big Al
08-31-2006, 06:39 PM
He pulled the heads. I saw the pictures. It detonated on the exhaust port with little cylinder damage. Al, he needed the extra fuel for the port work not the break-in. RC51, post the pictures so you can get more opinions.
I got ya, did it lean out?
He might need to have Tony Reprogram his PCU with a different map.
Al
STV_Keith
08-31-2006, 06:41 PM
When you pull the head, check the head gasket too. What CC are your heads anyway? What kind of compression did you see on the other holes?
I would definitely turn the ECU back to 0% or wherever it was before...you can run extra rich on oil for break-in (I go 32:1 with Merc Premium Plus - NOT synthetic), not extra fuel.
On Edit: Seeing US1's post, I can see adding fuel in certain spots for port work, but an overall increase may hurt driveability. Did you get the software the computer cable to program your PCU? That's the way to go.
When you pull the head, check the head gasket too. What CC are your heads anyway? What kind of compression did you see on the other holes?
I would definitely turn the ECU back to 0% or wherever it was before...you can run extra rich on oil for break-in (I go 32:1 with Merc Premium Plus - NOT synthetic), not extra fuel.
On Edit: Seeing US1's post, I can see adding fuel in certain spots for port work, but an overall increase may hurt driveability. Did you get the software the computer cable to program your PCU? That's the way to go.
Yea, that’s what I said. Just richen it from 4000 up. All I did to it was make the exhaust chest like a drag block. The port timing was stock 260 still. Another guy put it all together. Its bizarre it detonated with the same set up and 8% more fuel. He even went to 100-octane form 91. I though it might have over heated on the ramp during the first hour of running if the block wasn’t full of water or it sucked something up. He said it never had any power even the first time he drove it.
Here is a picture of the damage.
The Big Al
08-31-2006, 07:45 PM
Yep, that's lean.
Could have bad injector.
Wiring harness.
http://forums.screamandfly.com/forums/attachment.php?attachmentid=113970&d=1157071072
He kept the fuel rail totally sealed while it was apart but I told him dirt could have got into a fuel line on the boat during the rebuild. That could have plugged an injector. It definitely looks lean to me too.
when you get it back together tdc that cylinder with a piston stop and check timing, you might want to do all 6. and check for a double fire.
when you get it back together tdc that cylinder with a piston stop and check timing, you might want to do all 6. and check for a double fire.
That exactly what I do, all 6. I have found so many bad triggers.
Ok, as far as programing and fuel injectors go. The trip before my lower unit came loose and caused the damge to my crank splines my boat was running like a million bucks. It was my first trip out after sending my injectors to Tony. When he was cleaning them he informed me that four of the six injectors were bad. So, I had him install four new injectors on my fuel rail and calibrate them all. I am running 31cc heads and have been all season long. My compression before was always dead on @ 150 PSI. When I first put the heads on I was running two gallons of 110 to every three gallons of 91 premium pump. Mid season I stopped mixing in 2/3 and changed to 1/4 after a talk I had with Jay Smith. It always ran fine. After I recieve my fuel rail back from Tony I decided to take my box in to check on what % it was at. The tech informed me that he was getting a spuratic reading on the volt portion and that ment that I was getting a spuratic reading for the fuel mixture. So, I talked to Tony and he set me up with a PCU that had one of his curves in it based on the mild mods done to my motor.
In addition to buying the PCU I decided to cover all the avenues. So, I bought I new motor harness, new plugs, new Magnacore wire set, new air sensor,new water pump and several new gauges including a dual EGT gauge. I was just trying to go overboard and cover all the basis.
I took it out after putting all the goodies on my boat and it ran like a million bucks. Could not have been better. I ran it all day and was very happy. At the end of the day I was doing some solo speed runs when my boat felt like it was going into neutral. I hopped out of the boat and saw that the lower unit was loose. I got towed back to camp and took the boat out of the water. Saw that the front three studs backed out of the lower unit, the two in the back that come out of the mid section actually broke off. I was lucky not to have lost the lower unit and prop. When I pulled the lower unit out the drive shaft and crank splines were stripped off.
This real ****ter is that I had just spent 2,500 hundred on the Sport Master lower unit that I purchased off S & F which is where I bought the boat as well. As it turns out the guy I bought the lower unit from didn't use any locktite on the studs and they backed out. It never crossed my mind to check that the studs had locktite on them. So, let this be a lesson to anyone who buys something with studs in them, check for locktite. If I would have checked and seen that the studs needed locktite in the first place I would be a very happy camper right now with a great running boat and lots of money in my bank account.
Anyway, it was at this point in time that I needed a crank for the motor and a new drive shaft for the Sport Master lower unit. The lower unit was easy since the local shop had a good used one. I bought the crank from Marine Crankshaft and it was the wrong one. So I returned it and bought the correct one from John Marles. I took the motor off and had the local shop tear the motor down and reassemble it. While the motor was apart I decided to send the pistons to John Marles to have them top pinned. I also put new rings in the pistons and bought some lightweight wrist pins. In addition I decided to send the block to John Marles and have him to his magic to the exhaust cavity. The ports were left alone. Once I got the crank, pistons, block back from John I took it all down to the local shop and he assembled it.
When the motor was complete I picked it up at the local shop and installed it. John suggested I add more fuel to it because of the exhaust chest work he did. So, I called up Tony who did the original curve on the PCU and asked him how much I should go up based on the exhaust chest work. He suggested that I turn up the overall curve 8% for break in and then go down 4% after the motor is broken in and see how it runs.
Based on the facts you can see that basically nothing had changed between the motor coming apart while running perfect and when it went back together with the exception of turning the fuel up 8%
You should also know that I took the new injector rail off myself and put caps on them the moment I took in out of the motor and put it in a drawer for safe keeping. I didn't want to worry about getting a new injector dirty.
So, now to the day I put the boat in the water. I backed the trailer down and put the boat in the water. It started right up and idled smooth. I took the RPM's up to between 1500-2000 RPM's for around thirty minutes. Then I let it cool for quite some time. Then I started the boat up and it idle smooth out of the no wake zone. I then gave it gas to get on plane and it was very lazy and slow. The boat had a difficult time getting on plane. Once on plane the boat would not get over 5000 RPM's. So, I let it cool and checked things out. I was driving it around for about five minutes. I didn't see anything that popped out at me as being wrong. So, I floated for a while and let the motor cool for about two hours. I then started it up, idled smooth and tried it out again. This time it would not exceed about 4100-4200 RPM's and I took the boat out of the water. I didn't have more than about 10-15 minutes total running time on the water. The EGT's never read more than 900. The motor was running so rich that it left black all over my prop, mid section and lower unit. That has never been a problem before. As a matter of fact when I pulled the head off all three cylinders on that side had a pool of oil at the bottom of them.
When I did a compression check after getting home from the water I had 150 in five holes and my gauge would not register in hole #1. I checked the timing and it was OK as well. As you can see the piston detonated and got hot. I'm not sure why. The only thing I'm sure of is that it was running perfect before.
Those are the facts and I welcome any comments. Thanks
:mad:
--mirage1--
08-31-2006, 10:52 PM
Why did the ring rotate with end gap to exhaust port.
Kevin
Good question, didn't notice.
150aintenuff
09-01-2006, 12:21 AM
also as far as lazy it could have been retarded timing, you can have all the air and fuel in the world on a merc and it wont exceed 2500 under load before fgalling on its face and dieing.. lost a timing arm once and it was OH so Fun figuring that one out when we were 30 miles offshore.....
150aintenuff
09-01-2006, 12:30 AM
Yep, that's lean.
Could have bad injector.
Wiring harness.
http://forums.screamandfly.com/forums/attachment.php?attachmentid=113970&d=1157071072
ACTUALLY that looks WASHED as in the plug was so far out of timing that it neveractually fired off untill it got up to R's then it detonated due to the excess fuel charge... Lean would have atleast a bit of deposits... that looks totally clean...... also on the forged pistons... why the heat ..cool, refire and run??? fire it , allow it to ease up to temp and keep it there..
150aintenuff
09-01-2006, 12:32 AM
Why did the ring rotate with end gap to exhaust port.
Kevin
damaged piston top will allow the ring to spin due to breaking up and allowing the ring to climb and walk over the pin. or remove pin entirly when the piston breaks up
Why did the ring rotate with end gap to exhaust port.
Kevin
Thats not the end gap. It has top pin rings. These rings have a notch in the end for the pin.
--mirage1--
09-01-2006, 10:42 AM
A radial stop not a lateral stop so the ring broke.
--mirage1--
09-01-2006, 11:41 AM
Your right John M (US 1) about the radial ring. The picutre shows the top pin on the other side. Kinda hard to see if the ring sticking out is broken or. Without looking at the head, piston out, and the total cylinder to make a judement call.
Kevin
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