1987 Evinrude 88 SPL Low Compression one cylinder

[WilliamBecker88]

Hello Everyone,

I'm new to the boating community i bought my pontoon last year and used it around 15 times before it was winterized. This year i went to start it and it wont start so i got to digging, and ran a compression test. i have 3/4 of my cylinders at 110-120 PSI which is pretty good and my last one struggles to reach 30PSI. i have a scratched cylinder wall (see pictures) and was wondering if it would be worth my time and especially my money to have my local shop resleeve it and just rebuild it all my self. Any input would be great thanks! this is an 87 Evinrude 88 SPL motor on an 1987 Crestliner CrestIII 29' Pontoon.
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[emdsapmgr]

Re: 1987 Evinrude 88 SPL Low Compression one cylinder

Likely that the low compression cylinder lost the top ring on the piston. If you want to salvage this powerhead, it will need a complete teardown and inspection. Depending on how the block checks out, you may be able to re-use 3 pistons. I'd doubt it will need re-sleeving. The bad cylinder may need to be overbored slightly to clean up the cyl walls. It is permissible to overbore just one cylinder. If the head is pitted, the factory will recommend a new/replacement head. Best to put 4 new ringsets on during overhaul-along with one new piston. At some point, you'll want to diagnose the reason for the failure so it does not recur on the new powerhead. Looks like the rubber water diverters are correctly placed and the cooling passages around the cyls look normal. I'd start with an autopsy on the carb that feeds that bad cyl. You may have some debris lodged one of the jets-causing a lean condition which resulted in the damage.

 

[WilliamBecker88]

Re: 1987 Evinrude 88 SPL Low Compression one cylinder

Likely that the low compression cylinder lost the top ring on the piston. If you want to salvage this powerhead, it will need a complete teardown and inspection. Depending on how the block checks out, you may be able to re-use 3 pistons. I'd doubt it will need re-sleeving. The bad cylinder may need to be overbored slightly to clean up the cyl walls. It is permissible to overbore just one cylinder. If the head is pitted, the factory will recommend a new/replacement head. Best to put 4 new ringsets on during overhaul-along with one new piston. At some point, you'll want to diagnose the reason for the failure so it does not recur on the new powerhead. Looks like the rubber water diverters are correctly placed and the cooling passages around the cyls look normal. I'd start with an autopsy on the carb that feeds that bad cyl. You may have some debris lodged one of the jets-causing a lean condition which resulted in the damage.

so I can overbore just one cylinder and that will be ok? i thought if you bored one cylinder you have to bore all (in this case) four and get new pistons for all four?

 

[emdsapmgr]

Re: 1987 Evinrude 88 SPL Low Compression one cylinder

All pistons are designed to weigh the same, standard or oversize, so no problem with mixing one oversize and 3 standard. Factory pistons come in sizes up to .030 over. As long as you stay at .030 oversize (or less) you don't have to rejet that side of the carb either. You'll likely have to bore that one cyl for sure. You should check the other three cyl liners (holes) for taper and for roundness. If they are out of factory spec you may need to do the other 3 too. Hopefully not-esp if it's a low hour block. I'd clean up and re-use the other 3 pistons you have, if they spec out ok.