1988 Mariner 60 Top Cylinder problem

[Richardnpat]

I had my Mariner 60 blow the top cylinder. I then had it rebuilt and had the box replaced along with the rebuild (they said it was cross firing at times). About an hour after its break-in period, it did the same thing again. It never did seem to run smooth after the rebuild but I just attributed that to the heavy oil mix during the break-in period. It has been rebuilt again and they are getting ready to do some testing.

Anyone have some ideas as to possible places to look? Plug wires have been replaced as well as the #1 coil.

Also, somehow the keys are nowhere to be found since I took it to the shop. I am likely to tell them to just replace the ignition switch. Anyone have any idea on what that should cost?

Appreciate any help in diagnosing this problem. I want my boat back!

 

[Faztbullet]

Re: 1988 Mariner 60 Top Cylinder problem

What did the piston look like?? Was dome or sides damaged?? If dome was eroded, sounds like timing not set correctly or bad trigger. If dome is super clean with scuffs around piston skirt ,I would look at the jug casting and exhaust divider plate allowing water intrusion. If you can post picture of old and new pistons..

 

[Richardnpat]

Re: 1988 Mariner 60 Top Cylinder problem

Definitely damage to the top of the piston both times. One of my buddies is guessing that it is a pre-ignition, intermittent ignition, or cross firing of some sort but he and the shop are having a devil of a time pin-pointing it if it is that.

Of course I threw the last piston away thinking one rebuild would be sufficient. But it was definitely eroded on the top.

I will ask if he replaced the trigger, but I believe he already has done that.

Any other ideas? Could it have anything at all to do with the ignition switch - hey, I'm grabbing at straws here. The weather is improving and I wanna get to crabbing.

Thanks for any help.

 

[Faztbullet]

Re: 1988 Mariner 60 Top Cylinder problem

Start at the basic's.. 1-is engine overheating? 2-is timing properly set? 3-is this the corret set of spark plugs? 4- is engine over prop'ed? 5-was cylinder cleaned of old melted piston in the jug top? 6- carb high speed jet clean? If everything is ok ,I would index flywheel and check timing on all cylinders. It sounds like to me a ignition problem( trigger or pack or incorrect timing set-up)

 

[Silvertip]

Re: 1988 Mariner 60 Top Cylinder problem

The biggest mistake during a rebuild is not identifying the cause of the problem. Single cylinder failures are often due to fuel delivery (lean) problems. Routine spark plug readings can detect this condition so fuel system corrections can be made before damage is done. Water pump, thermostat and poppet valve replacement should also be done as part of the rebuild. And if you happen to have a really untrained tech he will be quick to blame the problem on E-10 (gasohol).

 

[Laddies]

Re: 1988 Mariner 60 Top Cylinder problem

I believe Silvertip hit the problem on the nose. Any time a dealer talks about cross fire on a ADI engine you should know he is trying to baffle you with BS. It just can not happen, it maybe out of time but each cyls. spark is independent of the others. If they try to tell you that crap when have them explain how it crossfires. Back to the key question most dealers have a master key ring and don't have to change the switch, just sell you a key. anouther reason to start looking for a differant service shop.

 

[Richardnpat]

Re: 1988 Mariner 60 Top Cylinder problem

Thanks guys. I talked to the owner of the shop and he said the key issue should be no big deal and that he should have a key that will fit my ignition. Aparently, his tech didn't want to look too hard.

As far as the spark issue goes, the work they are doing this time around is on their dime. At a point, I am leaning on them, and trying to push them to get the dang thing done, but trying to find the middle ground so that I actually get a working boat back.

They have now replaced the coil, they had already replaced the box and triggers in the initial rebuild. Is there any merit to the theory that possibly the coil is failing and releasing a spark out of time? They said it was a reach but so far it seems to have corrected the spark issue. They have only had it running for a few minutes and they didn't notice any problems. Today, they are supposed to run it in the tank for a while, then slowly put it under stress and check the timing and spark at that time.

The carb was also changed as part of the original rebuild as it was suspected to be the initial culprit.

I will ask them about the pump, thermostat, and poppet but I believe they did replace that stuff. A good friend of mine (engineer - not boat mechanic - but knows enough to baffle ME) has been overseeing the project when he has time. He had me replace the impeller before taking it out when I first bought the boat a couple years ago. I think he said something about that it was still in good shape but he had them replace it anyway. One other thing of note - both times the motor went out, the motor was not hot at all and it was pissing just fine.

Not sure if my blithering is helping anyone figure anything out or if I'm just clouding the water. I am trying to learn as much as possible about this stuff. I hate being ignorant. Put an irrigation system in front of me and there's no problem I can't fix. Put food in front of me and I'll tell you how it was made. Put a boat motor in front of me and just watch my eyes glaze over.