Loss of power in 1988 Evinrude 88 spl

[Dersu Uzala]

My 1988 Evinrude 88 spl ran fine for the first 20 minutes of a water skiing session. We switched skiers (both skiers were under 120 lbs) and the next time that I tried to throttle up, the engine was super sluggish and could only produce enough rpms to get up to about 11 mph. I dropped the passengers at the pier and tried to power up with just me in the boat. It was still very sluggish, but it slowly got up enough rpms to go 28 mph. Normally, the top end is around 34-35 mph. The motor starts fine as long as I give it a little throttle. It runs fine as long as I keep the throttle slightly above a low idle, but it does give off excessive exhaust. I ran carb cleaner spray through the carb, but it did not make any difference. When the motor is trying to build up rpms, it sounds like it's on the verge of accelerating, it just quite doesn't have the power to get up and go. Any thoughts on diagnosing the problem?

 

[havoc_squad]

Compression test first, spark gap tester test second.

What you are looking for is over 100 PSI on all cylinders, within 10% of each reading or less difference.

No point going further if compression test fails. You'll have to diagnose the problem before going any further if this occurs. If Mechanical issue then likely that would involve expensive rebuild.

Spark gap tester needs to jump 7/16's with nice white/blue spark.

If those two come back as good, when was the last time the engine was ran, how old is that gas in the tank, when was the last time the carbs were completely cleaned out and how regular is your fuel stabilization?

Carb spray doesn't tell people what you actually done to rebuild and clean the carb itself. People often clean carbs like they clean their hands, quickly and poorly.

 

[oldboat1]

Make sure there is no water in the gas (would see it at the bottom of a glass jar if you test a sample that way).

 

[Dersu Uzala]

You gave some great advice havoc_squad. I thought that it had to be fuel related or related to the coils. I fiddled with the coils and the connection between the coils and plugs for a few days before I took your advice. When I finally got around to checking the compression, I found 10 psi in one cylinder and 0 in another. I pulled the cover off the cylinders and discovered that the head gasket was blown and water had infiltrated the cylinder with 10 psi. The 0 cylinder was seriously gouged. My guess is that the head gasket failed some time ago, the motor ran acceptably on three cylinders and then the 0 cylinder suffered sudden and catastrophic failure. So now I have an 88 hp paper weight. Thanks for your help.​

 

[Crosbyman]

sell parts...:-(

 

[havoc_squad]

You gave some great advice havoc_squad. I thought that it had to be fuel related or related to the coils. I fiddled with the coils and the connection between the coils and plugs for a few days before I took your advice. When I finally got around to checking the compression, I found 10 psi in one cylinder and 0 in another. I pulled the cover off the cylinders and discovered that the head gasket was blown and water had infiltrated the cylinder with 10 psi. The 0 cylinder was seriously gouged. My guess is that the head gasket failed some time ago, the motor ran acceptably on three cylinders and then the 0 cylinder suffered sudden and catastrophic failure. So now I have an 88 hp paper weight. Thanks for your help.​

It might be a paperweight now but could be worth getting a reputable remanufactured replacement powerhead installed or searching for a similar model range used that has good compression.

If you go rebuild route with someone rebuilding yours, make first sure they do those regularly and have the reputation to put out good work.

1978 to 1991 I believe for the 85 hp to 115 hp crossflows can use the same lower unit the same driveshaft splines.

SEI lower unit replacements require ordering the correct driveshaft as those units use the newer two piece style of drive shaft.