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150 hp Johnson quits when warmed up

B

Bwark

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I have either a 1996 or 1999 150 hp Johnson Model J15GLEDS s/n G04124857. starts and idles great. Carbs have been overhauled. Both power packs are new. One cylinder has been oversized and piston and rings replaced in that cylinder and the rings replaced in other cylinders recently. The problem I am having is that when the engine warms up (generally after full throttle operation for a few minutes) the engine suddenly dies and will not restart until completely cooled off. Any Ideas?

Thanks,
Brian
 
In the model # the last letter is production related, the 2 letters before it are the model year. 'ED' of your J150GLEDS translates to a '96.

That condition sounds like a possible lean seizure or a heat seizure.....neither of which is good. You're either running lean in one or more cylinders or the motor is getting too hot. Have you confirmed the temp sensors are functional and the thermostats are operating properly?

Does the engine sputter or does it just die immediately? I suppose you could possibly have an ignition component getting too hot and it cuts out. Possibly your stator?
 
Thanks Kevinj.

I believe the thermostats are brand new also although I have not double checked their operation. The engine dies suddenly no sputtering. If the weather ever warms up I am planning to do a bore scope inspection of the cylinders. I suspect if the cylinders are grabbing the pistons and stopping the engine I would be able to see the evidence on the cylinder walls - agree?
 
BK560006.JPGBK560005.JPGBK560002.JPG
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BK560008.JPG these are the pictures I took with the borescope! pretty self explanatory I think. sorry about the sizing of the picture - not sure what happened.
 

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Looks like a lean seizure. Can you post pics of all 6 piston domes? The piston wash on the dome that is visible is a bit thin. You should see a clean spot by each intake port about the size of your thumb nail. Those tiny slivers of clean spots look like the cylinder was starved for fuel.

Did a shop do the work or you? It sounds to me the original cause of your first engine failure wasn’t solved during the rebuild resulting in the same problem again. Unfortunately this engine needs to come apart again. If a shop did the work will they warrantee the engine? If not it’s either rebuild again or you can just install a reman power head.
 
If they put a Seizco piston in they likely did not clearance it properly and it was never tempered when broken in. You have to let motor reach operating temp before WOT usage with Seizcos
 
faztbullet said:
If they put a Seizco piston in they likely did not clearance it properly and it was never tempered when broken in. You have to let motor reach operating temp before WOT usage with Seizcos
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I've not rebuilt an outboard before, but I've done several 2-stroke PWC engines. Wiseco pistons are definitely a fickle deal, so if that's what you have in the motor that could explain your problem. I've never had an issue with WSM pistons, but Wiseco definitely has to be up to operating temp before you give it the juice. If you don't, galled cylinder walls just like yours can happen.

KJ
 
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