120 mercruiser no power on acceleration

[83fiberskiff]

I have a 1983 120hp mercruiser. Im having issues with it losing power on acceleration cleaned the carb (yes accelerator pump is working good) changed points made sure timing is good changed mechanical pump to electric cause mechanical pumps kept going bad, idles good most of time (occasional mishap) free revs decent just acts up under load I’m at a loss! It’ll take off kinda slow get to 2400 rpms then just sputter and pop a little just sound like crap I’ll back off it then ease into it and sometimes it’ll slowly climb and reach about 35 to 3600 rpms WOT which it should have more rpms left (did before) please any help to figure this issue out would be appreciated! Thank you

 

[Benny67]

You probably have a fuel volume issue. Check your filters for clogs

 

[Scott Danforth]

Check the accelerator pump

 

[Scott Danforth]

Also, what is your compression numbers?

 

[83fiberskiff]

You probably have a fuel volume issue. Check your filters for clogs

Filters are new

 

[83fiberskiff]

Also, what is your compression numbers?

I’ll check that today

 

[Bondo]

I have a 1983 120hp mercruiser. Im having issues with it losing power on acceleration cleaned the carb (yes accelerator pump is working good) changed points made sure timing is good changed mechanical pump to electric cause mechanical pumps kept going bad, idles good most of time (occasional mishap) free revs decent just acts up under load I’m at a loss! It’ll take off kinda slow get to 2400 rpms then just sputter and pop a little just sound like crap I’ll back off it then ease into it and sometimes it’ll slowly climb and reach about 35 to 3600 rpms WOT which it should have more rpms left (did before) please any help to figure this issue out would be appreciated! Thank you

Ayuh,..... Welcome Aboard,..... Did you tear down, 'n rebuild the carb, or squirt some carb cleaner around on it, 'n call it "Cleaned",..??..??

 

[83fiberskiff]

I figured out issue only 50 psi in number 2 and 3 cylinders 1 and 4 have 140psi idk what went wrong

 

[Scott Danforth]

I figured out issue only 50 psi in number 2 and 3 cylinders 1 and 4 have 140psi idk what went wrong

most likely exhaust manifold is rusted thru and leaking into center cylinders, or you blew the head gasket.

do you boat in salt water?

time to do a leak down test, then start fixing.

 

[83fiberskiff]

most likely exhaust manifold is rusted thru and leaking into center cylinders, or you blew the head gasket.

do you boat in salt water?

time to do a leak down test, then start fixing.

No, just fresh water it will idle fine