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Potential Purchase - low compression

FLJetBoater

Jet Boat Junkie
Messages
741
Reaction score
283
Points
137
Boat Make
Yamaha
Year
2020
Boat Model
242 Limited S E-Series
Boat Length
24
I'm looking to buy a year newer than my existing boat, 2015 242 LS. Only 38 hours on the engines. Seller had Riva do a compression test on the engines and it came back 95/100/100/105 on STBD and 105/100/95/105 on PORT.

The boat had sat for a long time, I'm wondering if the batteries were low like mentioned on another thread, but again, wouldn't a dealership know that? What else would cause that low of compression on BOTH engines with only 38 hours?
 
My suggestion: Test Drive. Maybe meter was off. they are all within 10psi. If engine runs strong it could be poor technique taking the readings (WOT? how long did they crank?)
 
My suggestion: Test Drive. Maybe meter was off. they are all within 10psi. If engine runs strong it could be poor technique taking the readings (WOT? how long did they crank?)
I have no idea what procedure they followed. Engines cold/warm, how long cranked for, etc. Seller took it in and sent me the report from the dealer. I may try calling but I'm not sure they will talk to me - might have to get him to call with me.
 
Can you drive it? This is the best way to test the performance short of doing your own compression test.

I’m no expert but have done and seen compression tests done lots of times. +/- 5 lbs from 100 doesn’t really worry me.
 
Can you drive it? This is the best way to test the performance short of doing your own compression test.

I’m no expert but have done and seen compression tests done lots of times. +/- 5 lbs from 100 doesn’t really worry me.
Thanks. Yeah I am going to drive it tomorrow....
 
Try running some ring free through it and driving it hard. I had an issue with oil consumption in one engine. Ring free followed by sea foam in the next tank of gas and no more oil consumption. Sticky rings are not uncommon
 
Perfect. Good luck.
Picked it up yesterday. Ran great on the water we were up to 50mph @ almost 8000 rpm...Few small things that need to be fixed but other than that looks to be in great shape. only 38 hours!
 
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