302 wont turn over

[w1bcr]

hi all
the latest project boat a 1974 sea bird mercruiser w/ford 302
model 288204 last owner rebuilt motor and used it one season then
winterized it and it sat for 12 years
when i try to roll it over with a b bar on crank it goes maybe 1/2 to 1/3 around
then stops let it sit and turns but stops in a different spot
what could it be ??
out drive is off ,loosened belts on alt/raw water pump
pulled plugs all dry no rust
pulled valve covers and checked valves none stuck
all looks clean and dry,oil has slight milky tint to it but no antifreeze
what do i try now ??
jim

 

[Bondo]

Re: 302 wont turn over

View attachment 229952hi all
the latest project boat a 1974 sea bird mercruiser w/ford 302
model 288204 last owner rebuilt motor and used it one season then
winterized it and it sat for 12 years
when i try to roll it over with a b bar on crank it goes maybe 1/2 to 1/3 around
then stops let it sit and turns but stops in a different spot
what could it be ??
out drive is off ,loosened belts on alt/raw water pump
pulled plugs all dry no rust
pulled valve covers and checked valves none stuck
all looks clean and dry,oil has slight milky tint to it but no antifreeze
what do i try now ??
jim

Ayuh,... Welcome Aboard,.... How's the oil Level,..??

I guess ya keep takin' it apart til ya find the bind,....
I'd probably do that on a motor Stand, rather than in the boat,...

 

[wrench 3]

Re: 302 wont turn over

Turning again after it sits sounds like a hydraulic lock. Did you try to turn it over with the spark plugs out?

 

[w1bcr]

Re: 302 wont turn over

oil level is just a tad low
tried with plugs out no difference plugs are now back in loose

 

[MikDee]

Re: 302 wont turn over

Maybe your hitting a stuck open valve? Try pumping some air into the cylinders.

 

[w1bcr]

Re: 302 wont turn over

pulled valve covers and all valves move
if any water got into lifters could that do it ?
they all seemed to open all right

 

[CaptainMak]

Re: 302 wont turn over

Did you try putting in some Marvel Mystery Oil into the cylinders and let it sit in there a bit ? Not sure, but seized pistons is an option. Try to work the oil in there, try to turn, add a BIT more, try to turn. See if that helps.

 

[wrench 3]

Re: 302 wont turn over

The most likely problem with an engine that's been sitting that long is rust on the cylinder walls. But I don't know why it starts moving again by itself.
Oil every thing up good and work it back and forth.

 

[w1bcr]

Re: 302 wont turn over

Sunday i guess i will try dumping the old oil out and putting some mystery oil in cylinders
and try again

 

[w1bcr]

Re: 302 wont turn over

ok changed oil and found some water in it
let cylinders soak with mystery oil and that freed it up turns over now
and starts and runs
its a closed cooling system so and was still full of antifreeze
haven't tried running water through risers yet is there any way to test them ?
and should i be worried about the manifolds themselves ?

 

[CaptainMak]

Re: 302 wont turn over

ok changed oil and found some water in it
let cylinders soak with mystery oil and that freed it up turns over now
and starts and runs
its a closed cooling system so and was still full of antifreeze
haven't tried running water through risers yet is there any way to test them ?
and should i be worried about the manifolds themselves ?

I'd start a new thread as it will probably get more replies to the new question.. Glad at least the motor is turnin'

 

[haulnazz15]

Re: 302 wont turn over

You can pull the manifolds/risers and do an acetone test to check for leaks.

 

[wrench 3]

Re: 302 wont turn over

OK, so you ran it but haven't ran water through the risers! You probably need to rebuild the raw water pump now. Check the exhaust hoses at the risers and the exhaust flaps. If they're burnt, you may have seal problems in the drive.

 

[haulnazz15]

Re: 302 wont turn over

OK, so you ran it but haven't ran water through the risers! You probably need to rebuild the raw water pump now. Check the exhaust hoses at the risers and the exhaust flaps. If they're burnt, you may have seal problems in the drive.

He just said it starts and runs. If he only ran it for 20-30 seconds, he's probably okay. Now if it sat idling for several minutes, he may have melted the flappers/etc.

 

[wrench 3]

Re: 302 wont turn over

He just said it starts and runs. If he only ran it for 20-30 seconds, he's probably okay. Now if it sat idling for several minutes, he may have melted the flappers/etc.

Yes, but they say if you rev it up you can damage the water pump impeller in as little as 5 seconds.

 

[w1bcr]

Re: 302 wont turn over

Yes did run for a bit w/o raw water checking flappers and impellers is on the list thanks for all your help

 

[w1bcr]

Re: 302 wont turn over

And outdrive is still off so no worries there

 

[HT32BSX115]

Re: 302 wont turn over

Howdy,


Sounds like you may have had a leaking riser gasket. Even with closed cooling (unless you have "dryjoint" manifolds and risers which is pretty unlikely with a Ford engine) if a riser gasket leaked a bit after the engine was shut down, it would have allowed raw water to run back into one or more open exhaust valves.

That would cause enough corrosion in every cyl with an open exhaust valve to make the engine "stick".

Also, if it was salt water, it would have happened faster.

You said "closed cooling". Is it a half system (block only) or a "Full" system block and exhaust manifolds? Salt?

If it was "clunking" to a stop, I would suspect a stuck/bent/broken valve or piece of a valve.

In any case, If I had a "stuck" engine, I would be removing heads to look inside before I trusted that boat on a river with a waterfall at one end!!


73/Rick