1989 115 Merc low compression

[timguy]

Oil line cracked off and motor slowed down and froze up. Owner had Amsoil injector oil in it. After cool down it restarted and ran another minute or two. Froze again after slow down during WOT. Owner headed back to landing with kicker. He had shop hook up oil lines and has used boat up until now, burning about 3 tanks of fuel. He brought to me expressing concern of a bit less power since the freeze up, but no other issues. My warm compression test is 78, 78, 79, 76. I know my gauge is 10 psi low, so add 10 psi to each reading. Does this motor need overhaul? Is it going to fail him in the Ontario wilderness? It has been this way for 1 year but only about 50 gallons fuel have been run through it since the mishap. Thanks.

 

[fastjeff]

Power head is shot. Sorry.

Jeff

 

[timguy]

That's what I think too, just wanted an expert opinion. I feel anything below 100 or 110 psi on this motor is a red flag.

 

[flyingscott]

Those motors should be closer to 120 psi. Anything below that is hit and miss as far as them running good.

 

[faztbullet]

When it seized the damage was done...skirts was scuffed and will slowly continue o do damage as unit is ran.

 

[timguy]

That is what I figured too. He was running at near darkness and failed to catch the oil leak. Said it was not like running out of gas, but a steady slowdown, then locked up at WOT. After checking fuel supply and oil tank level, waiting about 5 minutes, it started right back up.