1989 yamaha 150 with low compression in 1 cylinder

crabbydad

Petty Officer 3rd Class
Joined
Apr 20, 2009
Messages
75
I'm going to look at a Grady white tournament tomorrow, 3 hr drive. The boat has been sitting for 3 or 4 years. The gas had been drained out of it a couple years ago during a storm to fuel a generator. The boat cleaned up nice. the guy to start it but said it doesn't even sputter and checked and its getting fire. Probably needs the carbs cleaned, no big problem there. he said it ran fine when he had it out last. he did a compression check and 1 cylinder is 60 psi and the others are 115-120 psi. My question is, what are the odds that the rings are stuck in the 1 cylinder? Anyone ever had a similar situation and how did it turn out?
thanks
 

ondarvr

Supreme Mariner
Joined
Apr 6, 2005
Messages
11,527
There's a chance that could be the issue, but there's no way to tell without running some brand of carbon removal product.
 

crabbydad

Petty Officer 3rd Class
Joined
Apr 20, 2009
Messages
75
Could stuck rings drop the compression that much? I need to think about it a little more, over a 3 hr drive. I have to price the boat figuring it needs to be taken apart to diagnose and fix.
 

ondarvr

Supreme Mariner
Joined
Apr 6, 2005
Messages
11,527
Without him doing any work to investigate what the problem is, the value of the motor is only its weight in scrap aluminum.

I would not bet on the problem being stuck rings.
 

tommarvin

Ensign
Joined
Nov 22, 2015
Messages
999
If you really really want a Grady, a six hour round trip drive is not very long, we drove 16 hours.
I would get a leakdown tester at HF for 40 bucks and do a leakdown test for a compression test it's fast easy,safe. you don't turn the motor on,you-tube explains it perfect. Offer the guy what the boat only without the motor is worth will he sell you the boat for cheap because # 1 is 60psi..
You drive home do the leak down test, if #1 cylinder is not 60psi,but 115-120 psi you stole the boat, If #1 is 60 psi you paid only boat cost .
Are you willing to work on the motor, take the head off look at # 1 cylinder turn the flywheel , any scoring, does the top ring move freely
 
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