I am looking to buy a 27 fountain and just had a compression test done on it. It’s a 502 mag with 166hrs on it. All the cylinders were around 150 except #5. It was 110. Any ideas on what the cause could be and how much it would be to fix. I know its hard to tell without pulling the motor apart. I am trying to figure out how much to drop my offer that I made him. Should I bail out on the deal?

Thanks
Rob

With low hours like that I would suspect valve issues due to a failed injector. I tulipped 3 valves on one of mine due to low flow from the injectors. You could have a leakdown test done, that should tell if it's valve issues for sure.

you can shoot some reg oil in the cyl and re-ck if it goes up then you have a piston/ring issue(doubtfull though) my bet is a valve..Rob

Get a leakdown test performed and it will tell you if it is valves or rings and then you can accurately make an offer based on that.

my27fountain was the same way when i bought it.it is a 94 502 mpi,mag.it had 395hrs when i bought and 6 was week,[guy let the riser gasket leak].i used that as a barging tool also.knocked off 600 bucks.with few hours on your motor,i would not suppect that issue,but the can leak from the inside out.maybe it got a back wash and hurt a valve.hope this helps

did it ever get hot?