318/392 Stroker Motors

Fastjeff
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Re: 318/392 Stroker Motors

Postby Fastjeff » Mon Jul 08, 2019 6:27 am

Unless some kinda metal bug ate your impeller, I doubt if the circulating pump is the problem. (Their seals leak, that's all.)

Very easy for the strainer gasket--that you think is in there okay--to leak air. I replaced that fool thing with a homemade O-ring made from 3/16 vacuum hose glued together with a wire inserted. Easy to do and it NEVER leaked again.

Jeff
"We live at the bottom of an ocean of air, not at the top." General Marvage Slatington

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Busia
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Re: 318/392 Stroker Motors

Postby Busia » Mon Jul 08, 2019 9:30 am

I would take the T-stat out completely. The engine won't heat up as fast but otherwise will be fine. Run it for a while and see if you still have the problem. Often there is nothing wrong, just air trapped in the housing and needs to be bled. With air trapped you have no coolant there, so the t-stat never heats up and opens. Or the t-stat is bad. ( you can drill a small hole in the t-stat to help it by pass some fluid and force any air out )
To check for air leaks on the suction side I would have it running and pour water over each possible leak point. Use a garden hose or a bucket of water. See if it sucks in water where it might be sucking in air.
BUSIA
located in Ketchikan, Alaska. Gods country
32 foot Marinette express. (no fly bridge)
twin 350 Crusader (Chev 350) engines
1:1 Borg Warner velvet drive transmissions
Closed cooling (antifreeze in the engine)
Proud to be retired IBEW

Trowerpower
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Re: 318/392 Stroker Motors

Postby Trowerpower » Mon Jul 08, 2019 4:56 pm

Thanks for your suggestions! Next time down i will try them, next weekend.
Trower Power
1987 32ft Marinette Sedan Flybridge
Blue Sky
twin 392 Chrysler Stroker Motors
Performance Distributors
750 Edlebrocks
fresh water cooled
1.5 to 1 velva-drives
Onan 6.5kw gen set

Trowerpower
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Re: 318/392 Stroker Motors

Postby Trowerpower » Mon Jul 08, 2019 5:07 pm

I replaced the thermostat with a new 140 degree stat. In the process i found two impeller tips wedged in the two smaller holes of the housing. Lord knows how long they have been there. I thought that was the problem but nope. No change. The cast housing is very rusty, will replace it with the revised one soon.
Trower Power
1987 32ft Marinette Sedan Flybridge
Blue Sky
twin 392 Chrysler Stroker Motors
Performance Distributors
750 Edlebrocks
fresh water cooled
1.5 to 1 velva-drives
Onan 6.5kw gen set

Fastjeff
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Posts: 1116
Joined: Sat Jul 12, 2014 5:06 am
Location: Rock Halll, MD
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Re: 318/392 Stroker Motors

Postby Fastjeff » Mon Jul 08, 2019 5:48 pm

That'll do it! Had an impeller grenade on me as well and plug up the starboard side of the system.

Jeff
"We live at the bottom of an ocean of air, not at the top." General Marvage Slatington

Trowerpower
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Re: 318/392 Stroker Motors

Postby Trowerpower » Wed Jul 17, 2019 3:29 pm

Tomorrow, new thermostat housing and new thermostat, will install a different washer/gasket on the sea strainer stud, check transmission oil cooler for a restriction, inspect all hoses. Will pull spark plugs to sure its not running lean (i doubt it).
Trower Power
1987 32ft Marinette Sedan Flybridge
Blue Sky
twin 392 Chrysler Stroker Motors
Performance Distributors
750 Edlebrocks
fresh water cooled
1.5 to 1 velva-drives
Onan 6.5kw gen set