Help please! 90hp johnson Issues

My 13 year son just bought his first boat with his lawn mowing $$$, got it home and tried it out today...It seems to have a few problems (1989 90 hp vro 4 cyl) and I'm starting to think that me and my son got hood winked... The engine looks very clean but upon close inspection I found that a lot of it has been repainted pretty well, maybe hiding things.

The Main Concern...I did a compression check (i didnt do it warmed up and will tomorrow) but 3 of the chambers are all around 100-110, but one (top right) has only 85 lbs. When I had the plugs out I looked inside and you can see two little angular dings in the top of the piston on that 85lb chamber?? I'm not an expert, but this doesnt seem good? Is this a serious problem to be concerned about, is there a broken ring in there?? The seller told us that the compression was checked and was fine and the same in all cyl....but this doesnt seem to be the case.

Concern #2 I don't know if this is related, but when we test drove the boat, It starts fine and runs well especially at high speed, but at low speed it begins to bog itself down and after a little while it eventually quits. it will start right up again and if you speed up, it jumps up to speed, does not go there gradually, and if you speed up before it starts to bog down again your fine. But you seen to have to push by the just above idle speed and then it gets going??? Maybe this is related, maybe the carbs need cleaning and its just a tune up issue???

Concern #3 The cooling water coming out of the side stream is cold, not even warm, and if you touch the heads after its warmed up, they are cool as can be. At first I thought good, not overheating, but then I wondered if that is actually a problem??

I'm pretty mechanical and don't mind fixing some stuff, but I dont think I would get into an engine rebuild, (especially since the bottom two bolts on the head are croded to the point where they are much smaller than the rest of the head bolts on that side)

I havnt told my son all this yet, but I'm concerned that maybe this engine has big problems??? And since he spent every penny he had buying the boat this would be an issue for him and me!

Please tell me I'm overreacting and that I should clean the carbs, decarb the cyl, replace the thermostat...and it should go for a long time ---- or should I be calling the seller to have the difficult discussion??

Thanks much for any thoughts, I know this is a lot.

Wayne & Josh

Re: Help please! 90hp johnson Issues

your overreacting and that I should clean the carbs, decarb the cyl, replace the thermostat...and it should go for a long time

Is the vro hooked up?

Also run a can of seafoam maybe?

Re: Help please! 90hp johnson Issues

Yes, you're overreacting for the most part. Do as you suggested yourself and with some maintenance it should be up and running well in no time.

The only thing that would worry me on that list is the 85psi in one cylinder and the corrosion on the head bolts. The low pressure may come back up with a decarb procedure but if it doesn't you will need to pull the head and take a closer look.

That brings you to the corroded head bolts problem. Be very careful not to break the bolts off when/if you go to remove the head. Let them soak in some wd40 or pb blaster overnight before attempting to remove.

Other than that, sounds like you got yourself a great father-son project

Re: Help please! 90hp johnson Issues

The VRO is hooked up, the engine alarm was coming on and I was assuming that it was related to oil. I found some instructions in the manual about priming the oil vro and i did that -- then I did see the oil going up in the little clear tube by the vro pump. So i'm hoping that that was the problem, but have not tried it yet. Is there a way to really know if its pumping other than the alarm?

Re: Help please! 90hp johnson Issues

The 85 cyl is the thing that worries me too, that is the main thing that wories me since that repair may be over my head. And those head bolts, most look great but the bottom two look like hex heads, but they look to be a size smaller that all the others - not because they are smaller, but that they have been croded away. I'm not sure how you would even get a socket to fit them, maybe file the sides of teh hex til it fits a socket??

If the 85 is a problem, what would it be and how would you go about fixing it?

Re: Help please! 90hp johnson Issues

On concern #3, if it's running that cool, there's a possibility someone took the thermostats out completely, which is generally not recommended.