compression test done-do engine restore sealants work???

keltie

Cadet
Joined
Jul 4, 2004
Messages
16
Ok the info I have on the boat...<br /> merc 2.5 1988 renkin with 3.0 carb motot rebuilt by previous owner<br /><br />Compression<br />2 end cylinders are at 150<br />2 center cylinders are at 120-125<br />He also said that there is lots of blow by, and the problem could be a head<br />gasket...however, you dont know until it is taken apart. The problem could<br />be more serious, such as a complete rebuild.<br /> <br />Timing<br />Menhanic it reset 8 degrees<br /> <br />He wasnt sure on the condensor in the dist and he did not do a recheck once<br />he reset the timing so im not sure. He did suggest to switch to electronic<br />ignition distributor....check the cost<br /> <br />He recommended for the drop in compression to use 4 cylinder engine restore.<br />it goes with the oil and is supposed to seal any gouges in the cylinder<br />wall. what do you think about the sealant option??<br /> <br />I am hoping to get a 15deg prop to check it out as well to get some more<br />performance/torque<br /> <br />when running the boat on water rpms at wot were 4000 with 2 in the boat and only 3500 with 5 adutlts. <br /><br />any suggestions
 

Blk-n-Blu

Master Chief Petty Officer
Joined
May 12, 2004
Messages
821
Re: compression test done-do engine restore sealants work???

Try a product called Rislone engine restorer for "FOUR STROKE" motors usually available at Pep Boys or Autozone type stores.
 

kcjefff

Seaman Apprentice
Joined
Jun 29, 2004
Messages
41
Re: compression test done-do engine restore sealants work???

I could be wrong, but I thought your lowest cylinder compression just had to be within 75% of the highest.<br /><br />So for your 150, your low should be at least 112.5, which it is. Anyone can correct me if I am wrong, but I don't see an issue there on your compression.
 

goodtimeguy

Cadet
Joined
Jul 14, 2004
Messages
16
Re: compression test done-do engine restore sealants work???

from my experiance with auto engines is that it is a bad idea. do it if you like but these additives contaminate the inside of the engine and make doing any rebuilding alot more work. also i think people give the products alot more credit than they are worth. you've already got a problem so the couple of bucks that it costs you, you might get lucky. and if it doesn't hey your not out that much.
 

goodtimeguy

Cadet
Joined
Jul 14, 2004
Messages
16
Re: compression test done-do engine restore sealants work???

kcjefff is right i would try decarbonizing the engine and check the squeize again with the throttle wide open also check the engine vacum as this is atrue indcation of engine condition atleast 16 to 20 inches at idle
 

rodbolt

Supreme Mariner
Joined
Sep 1, 2003
Messages
20,066
Re: compression test done-do engine restore sealants work???

hello<br /> a leakdown test is in order. that will tell you if its rings,gaskets or valves. blowby is piston rings. hence the term. dont use snake oil. it does not work and usually causes more problems. the more weight you add the harder the engine must work. so with 5 adults you may need a smaller prop than with just 2.<br /> good luck and keep posting
 
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