Optimax 225 compression test questions

[peiserma]

I went to look at a 1987 Wellcraft V20 with a 2000 Optimax 225 HP.

The owner says he hasn't used it in 2 years (he has four other boats, three of them sitting in his backyard) but that the motor ran the last time he used it. I just did a compression test, and the numbers are much lower than the repair manual says. Looking at the engine from the rear, the numbers are:

65 70
95 75
65 60

But I do not know what these numbers mean, especially for a motor that has been sitting for two years. Could it be that the rings just need some lubrication to seal properly?

Thanks for any feedack.

 

[JB]

Re: Optimax 225 compression test questions

Those are awful on the surface, but as you say, the engine has been idle for a long time.

I wouldn't consider the psi numbers too low, but they do differ much too much.

Get her runnning and do a complete decarb, then do a correct compression test. Do not get paranoid about psi. Get paranoid about the spread. It should be 10% or less.

 

[peiserma]

Re: Optimax 225 compression test questions

Thanks for the reply.

The 2-year old gas is still in the tank. To get it running i would want to purge the fuel, change the oil on the motor and gearcase, lubricate the cylinders, and change all the spark plugs. The motor is fuel injected, so perhaps some injector cleaner (I imagine you use SeaFoam on these engines?) would be a good idea. The injectors might be gunked up from the old fuel by now.

Since I haven't bought the boat yet, doing all that work poses a problem : I'm not sure if the seller would be OK with it. Do you think its worth asking?