mercruiser 4.3l 175hp down on compresion on cyl 6 only reading 85 psiu

hughesy1

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My mercruiser. 4.3l 175 HP is down on compresion but the worst is only reading 85psi and is making an ireguar tapping noise any tips guys?i
 

tpenfield

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Re: mercruiser 4.3l 175hp down on compresion on cyl 6 only reading 85 psiu

Welcome to iBoats . . .

A bit more background and information is always helpful, so that you get good 'on-target' responses. It could be a wide range of issues so more info will help narrow it down.

List all of the cylinders and the circumstances surrounding the issue, etc.

That is my tip for the day.
 

Bondo

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Re: mercruiser 4.3l 175hp down on compresion on cyl 6 only reading 85 psiu

My mercruiser. 4.3l 175 HP is down on compresion but the worst is only reading 85psi and is making an ireguar tapping noise any tips guys?i

Ayuh,.... Welcome Aboard,.... With only that tiny bit of Info, I'd guess yer lookin' at a rebuild or replacement...

Do a leak-down test, 'n see if it's the valves, or rings...
 

tpenfield

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Re: mercruiser 4.3l 175hp down on compresion on cyl 6 only reading 85 psiu

Ayuh,.... Welcome Aboard,.... With only that tiny bit of Info, I'd guess yer lookin' at a rebuild or replacement...

Do a leak-down test, 'n see if it's the valves, or rings...

85 psi with an irregular ticking noise? Has to be the muffler bearings . . . :D
 

nola mike

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Re: mercruiser 4.3l 175hp down on compresion on cyl 6 only reading 85 psiu

Ayuh,.... Welcome Aboard,.... With only that tiny bit of Info, I'd guess yer lookin' at a rebuild or replacement...

Do a leak-down test, 'n see if it's the valves, or rings...
Could also just pull the valve cover and see if anything obvious strikes you...
 

hughesy1

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Re: mercruiser 4.3l 175hp down on compresion on cyl 6 only reading 85 psiu

the fuel problem is dirty fuel i belive, the other cyclinders are pushing 134 - 161 psi it should have 180 also the noise is coming from the rear left when looking at front of engine but its around the area of cyclinder 6 with only 85psi the revs are only 3900 at max and accelartion is well down
 

nola mike

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Re: mercruiser 4.3l 175hp down on compresion on cyl 6 only reading 85 psiu

what fuel problem? Doesn't sound like fuel is causing your symptoms. Your other compression numbers are ok.
 

hughesy1

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Re: mercruiser 4.3l 175hp down on compresion on cyl 6 only reading 85 psiu

fuel problem is uunrelated it was dirty fuel in tank the compresion problem is the one i need answears too thanks
 
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