1999 3.0 mercruiser

[Dj1]

hi there forum yes im a newbie and im in need of some help to see if its even worth fixing this boat... so i have a boat with a 3.0 mercruiser in it. the boat wasnt winterize not sure if the block is cracked but water seems to be coming out of somewhere towards the back of the engine. (I was told i didnt see it) anyways i pulled the plugs and they seem fine other then some rust building around the nut. did a compression test and the first two read 120 the 3rd 90 and the 4th 60. i did it with a remote switch. however the water and oil never mixed and the oil looks fine.... any suggestions would be helpful and highly appreciated.... thanks

 

[alldodge]

Coming from the rear of the block it may have just pushed a core plug out, and if so its an easy fix. Need to pull the motor to find out

Compression numbers are low, don't know if its rungs or valves. Need to get it to run a bit and then recheck compression and do a leak down test. Pull the motor and place on blocks or a stand, this way you could give the motor a good look

 

[Dj1]

thanks for the reply i was thinking of taking head off to inspect

 

[alldodge]

If its leaking from the rear of the block, the motor has to come out

 

[Dj1]

well i just poured some Mystery Oil in gonna see sunday if i get a different reading and gonna try to turn her over to see if i can see exactly where its leaking from. will post pictures as well.... thanks for the replies....

 

[Bondo]

Ayuh,..... There's a core plug, behind the flywheel,.....

Pull the motor, 'n replace that core plug, 'n try it,....
Ya might be Lucky, 'n that's the only damage,.....

 

[Dj1]

well i found a crack guess im gonna have to get another engine. them damn 3.0 mercruiser engine are hard to come by i see.smh would another engine other then mercruiser fit it

 

[Bondo]

smh would another engine other then mercruiser fit it

Ayuh,.... Yer options are another 3.0l, or a 2.5l, from a boat,.....

 

[alldodge]

MM is out of stock

Found 3.0 block at ebay for $995 and full motor reman at summit
https://www.summitracing.com/parts/...5mqKucV13qV6d5hAZWdLEPWNpkZFvkF4aAo0uEALw_wcB