Compression

[Ranger330]

#1 is 120psi
#2 is 120 psi
#3 is 35 psi
#4 is 115 psi
On a 1983 90 hp Evinrude
What are my options?

 

[racerone]

Remove cylinder head for inspection.----My guess is that you have broken piston rings which is very common.-----Motor will need to be rebuilt if that is in fact what is wrong.

 

[Ranger330]

What are we talking in cost for a boat mech. Assuming $75 per hour labor rate? I have rebuilt carbs and replaced impeller but never been inside engine.

 

[boobie]

Pull the head first and see what you find. It could be just a blown head gasket. Easy to fix.

 

[Ranger330]

Here is a little more info: I was running down the lake yesterday at about 5000 rpm when the engine started shaking and then just shut down. It started back up but was missing really bad. I idled back to the dock and shut it down for a few minutes. It never started back up. Also there is oil running down the sides of the engine from under the cowl. I will start to pull head off to see what it looks like.

 

[johnson89]

I just rebuilt a 1989 90 Johnson....# 3 cyl. had busted ring.....central fl shops wanted 2500.00 to rebuild....I did it myself 1050.00 give or take....bored all 4 cyls...this was about 4 months ago and is running fine....this site helped me out alot

 

[emdsapmgr]

You can replace just one piston-(even an oversize) that's an acceptable repair. ( Assuming the other 3 pistons are not too egg-shaped with age.) You will need to hone and put new ringsets on all 4 pistons. The powerhead will have to come off, so you may find that the powerhead base gasket has failed-the reason for the oil running down the midsection-so you'll fix that when you reassemble. If the ring let go, you may find that the head on one side is badly damaged-perhaps to the point it will need to be replaced.

 

[Ranger330]

Thanks for all the replies! Any way you look at it.....it's not good. Even if I have to rebuild and try it myself I'm afraid I'll be out at least $1000.

 

[racerone]

I have numerous V-4 motors with the same failure for parts and rebuild.---Some for free because big shops just do not rebuild them anymore.---Same failure will happen to most of these engines, it is just the design of the top ring that is the problem.

 

[64osby]

If it's in the budget you might look for a replacement. $1000 or less can often buy an ugly project boat with a great motor. Dump the boat after salvaging what is good. Sell the trailer and boat parts. Then part out your parts motor. Some have done this to end up with a free or nearly free motor.