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Stock Compression

jpass

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What is the stock compression for the 155HP 1.5L engines? Is it 120psi?
 

Speedling

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Believe so. Lots of variables make that a ballpark. Do they all read within a few psi of each other?
 

jpass

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Yes, they all read right at 120.
 

Cobra Jet Steering LLC

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I believe 165 is more like it but you could be getting a bad reading or have a bad gauge , it is difficult to get a good reading without the correct fitting to go down where the plugs sit
 

jpass

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That's what the dealer said. I can always test myself.

Is there anything special I need to do aside from the normal procedure (warm motor, remove all plugs, disconnect coils, start, WOT)?
 

Cobra Jet Steering LLC

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nope that covers it
 

Cobra Jet Steering LLC

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why are you concerned about your compression?
if you tell me the year and the symptom I may be able to help point you in the correct direction I had 2 of those for several years
 
Last edited:

jpass

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I'm not too concerned about compression. I was just questioning what stock was considering we just purchased it and the dealer said she ran 120 in all 6 cylonders.

Our V8 351 Windsor showed 150-155 between all 8 cylinders with 1820 hours on the 23 year old girl. Brand new motor has 160, so she was in great shape.

I had no idea where the compression should have been on our new boat and wanted to know what stock compression should be.

We only ran her twice and she seems to run just fine.
 

Cobra Jet Steering LLC

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ok so no problem means don't worry about it they just did not do the compression check correctly. I have seen the 4 tec engines hit upward to 180 psi if all read the same no worries.
 
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