Urgent Compression Test Question

hdl

Cadet
Joined
Aug 20, 2009
Messages
13
I am considering purchasing a 2000 Fountain 29 CC w twin Mercury 225 EFI's. The following are the results from a comp test I did today along with the hours per the computer. Some of you Mercury GURUS let me know what you think also if you have an opinion regarding these Motors and the Fountain-I am mainly looking for input on the motors though. The motors have only been ran twice (very briefly maybe 30 minutes) in at least 9 months.

Thanks alot.

Port 110,115,112,114,110,120
Hours
0-1000=162hrs,1000-2000=51,2000-3000=30,3000-4000=91,4000-5000=58 and 5000-rpm limit 8

Stbd 100,115,120,112,115,118
Hours
0-1000=150hrs,1000-2000=62,2000-3000=22,3000-4000=94,4000-5000=65, and 5000-rpm limit 7
 

emckelvy

Commander
Joined
Jan 16, 2004
Messages
2,506
Re: Urgent Compression Test Question

Compressions aren't as close as you'd want to see. I start worrying when there's more than 5 psi variance. Don't like to see 10 psi or more.

Both motors likely need a serious decarbonization then a good run, followed by another compression check. If the readings even themselves out, not so bad. If not, the motors may have issues.

If you can have a leakdown test done it'll pinpoint any problems that a compression check can't find.

Considering the amount of $$$ you're likely looking at for a rig like this, it'd well be worth having the leakdown check done.

Here's some good info on decarbonizing treatments:

http://forums.iboats.com/showthread.php?t=158076&highlight=seafoam
 
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