1995 88HP SPL Johnson Compression Test Results

[smak90]

I've got a used boat that's always been a little hard to start. Going across lake last week at WOT the engine just flat out died with no warning. Waited about a minute before attempting restart and it fired up fine and I went on my way. Last time I was operating at WOT (about 4 months ago) the engine horn went off so I shut her down and waited about a minute. When I fired it back up, the horn continued to go off, then after running engine for 30 seconds at idle the horn shut off. I've been using the boat at least once every 2 weeks this past winter but never running at WOT. Ususally just running at 3/4 throttle maximum.

I did a compression test today - first dry and the wet. Engine was cold. The engine had last been run last weekend (6 days ago). The results did not change between the 2 tests.
My results were the following:
Top Left: 105
Bottom Left: 110
Top Right (driver's side): 70
Bottom Right: 115

I know this is very bad and most likely means I need a rebuild My question is can anything be done besides a complete tear-down and rebuild? What is the most likely cause of this low compression on the one cylinder.

Also, how long can the engine operate under these conditions if I don't operate above half throttle? The Crappie are getting ready to spawn here in Central Texas and I don't want to miss it due to my boat being in the shop.

Thanks in advance for your responses,
Scott

 

[tashasdaddy]

Re: 1995 88HP SPL Johnson Compression Test Results

sounds like you picked up some on the water inlet, and it ran hot. possibly a blown head gasket or exhaust gasket. i would pull that head and inspect. you will do more damage if you keep running it.

 

[rodbolt]

Re: 1995 88HP SPL Johnson Compression Test Results

yep its head pulling time, continued running WILL finnish it off and possibly make a simple 4 hole bore and piston job into a power head replacement.
as the hot gases pass the scoures in the piston/cyl wall it contaminates the incoming af/oil charge leading to crank failures.
usually #1 burns due to overheat from either corroded water restrictors,failed pump or a stuck T-stat.