Logo
FULL SITE MENU

Whats the best 'soloution' to enable me to turn my engine over by hand?

E

english_man_in_norway

Contributing Member
I have a mercruiser 4.3 1992,i have the heads off due to an overheat problem,but can't turn the engine over by hand,do i soak the cylinders with a freeing agent? And if so whats best?
 
with the heads off , with a ratchet and socket , on the crank you should be able to move the crankshaft , with not much effort.


If you ran this with no/low oil it is possible the piston skirts have galled into the cylinder wall.

any overheating details as this would help with how to get around this .
 
Thanks for the input everyone,it wasn't low on oil at the time,I think its just the salt water thats caused some rust in the cylinders,as the top of some of the pistons were a bit 'crusty',if I can't find 'blaster',i'l try the 'pickling' method.
 
english_man_in_norway said:
Thanks for the input everyone,it wasn't low on oil at the time,I think its just the salt water thats caused some rust in the cylinders,as the top of some of the pistons were a bit 'crusty',if I can't find 'blaster',i'l try the 'pickling' method.
Click to expand...

If you got seawater in those combustion chambers and it sat for a week or so ,just get another motor.
 
I have broken a chevy small block that was rusted free by soaking each piston in pb blaster and taking a short 2x4 and a hammer and hit each piston several times lightly until it was free. but if its rusted badly and there is deep pitting in the cylinder wall you will need to have it bored out and get new pistons, rings rod bearings. well a complete rebuild kit and have the cam turned if its out of spec.
 
Last edited:
Thanks,i put in the pickling soloution,i'l check it in a couple of days & if it isn't free,i will try tapping it gently,don't think its too badly rusted,as the cylinder walls thats showing above a couple of pistons look fine,it was just rusted on the top of two pistons.
 
Just how long did it sit with water in the cylinders?
Wny not just use the starter to try and free it up? If the starter cant free it, it`s time for a new motor
 
A Couple of weeks,but I didn't think there was much water in there,as it was only a couple of plugs that were a bit rusty,there was no water in the oil either,but yeh I was actually going to try cranking the starter,to free it as a last resort,I'm fairly new to all this marine mechanical 'tinkering',but today I was looking at the manifolds that I'd taken off, on one side of the manifolds there is 3 inlets/outlets,I presume the middle one is water intake & the 2 outer ones are exhaust outlets? Just that one of the manifolds outer ones had a layer of soft carbon indicating exhaust,but the other side manifold all 3 indicated rust,so does that point out to anything other than obviously that its being throughing water out throuygh the exhaust on that side?
 
Thanks chiefalen & bt doctor a combination of the soaking & a couple of flicks with the starter,enabled me to turn over by hand once again! chiefalen you said you know a few more 'tricks',I'm all 'ears'.
 
Drain it and when you fill it fill it with oil and 1/2 quart diesel and run it for a half hour. Drain it new filter new oil run it again with fresh oil for a day.

And then one more change. Your done. You might want a new set of plugs also.

Your motor is going to get as good as it gets, check compression.
 
So the compression will be the same on all cylinders. With the heads off, right. Just jerkin ur chain Chief. Carry on.
TxGalz Dah
 
Back
Top