Siezed up

[cyrdg]

I have a 75hp Mariner Outboard that is siezed up tight. Here is what happened. Motor ran all week. The last day it started an ran rough for a few seconds then quit. Tried again and started, ran rough about 10 seconds quit. The engine would barely turn then stopped turning completely. Got it out of the water and found the lower unit oil plug was missing not sure how long. Now i have verified the starter is good. Cannot turn the prop when in gear cannot turn the flywheel.. Question: how can i tell what is siezed the lower unit or the engine? Thanks in advance.

 

[FLATHEAD MAC]

Re: Siezed up

separate lu from upper . Prob lu seized from lack of oil (bearings). With lu off you can check to see if you can turn the motor over,

good luck

 

[GA_Boater]

Re: Siezed up

Can you turn the prop in neutral? About the only way to see which is locked up is drop the L/U and see if the motor spins.

 

[cyrdg]

Re: Siezed up

The prop does turn in neutral. How difficult is taking off the lower unit? I work on lawn mowers, tractors, trucks etc. but never worked on a boat motor? Thanks for the help.

 

[RogersJetboat454]

Re: Siezed up

Fairly simple and strait forward as it's what you have to do at least every 2-3 years to change the water pump impeller.

 

[carholme]

Re: Siezed up

cyrdg;

What is the s/n of your engine and I'll try to get some service manual information for you.

Gerry

 

[GA_Boater]

Re: Siezed up

cy - easy job. The only slightly special tool you need is a 3/8" hex wrench for the trim fin. Only 4 or 6 nuts/bolts and the L/U drops straight down. The shaft may hang up a little coming out of the power head, but if you have to pry on it be gentle. Really an easy job.