standard or reverse rotation?

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russ67chevelle

Cadet
Joined
Jul 8, 2010
Messages
16
sorry probably covered 100 times, but how can u tell if engine is reverse or standard rotation when engine is out of boat. any visual signs>? would the crank post thread for pulley be left hand thread if reverse rotation? i dont know if i can spin motor, probably froze but not sure. thanks in advance
 
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ljsweeney

Seaman
Joined
May 23, 2011
Messages
54
Re: standard or reverse rotation?

Check the firing order (should be visible on the motor) for your displacement/manufacturer. For example, a GM 8 cyl engine will fire 1-8-4-3-6-5-7-2 for standard rotation, and 1-2-7-5-6-3-4-8 for reverse rotation. I got this info from here: http://www.rapidomarine.com/default.aspx?p=/firing_orders.aspx

You can check that website, find your engine, reference the firing order, and you're done.

Good luck.
 
S

sw33ttooth

Chief Petty Officer
Joined
Apr 24, 2011
Messages
498
Re: standard or reverse rotation?

OMC never used reverse rotation engines afaik.
Click to expand...

pretty sure they didnt as well, also i dont know why they would put a reverse rotation into a boat with a single engine? i think they only use with double, triple, and quads just my thoery any how.
 
Bondo

Bondo

Moderator
Staff member
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Apr 17, 2002
Messages
70,525
Re: standard or reverse rotation?

russ67chevelle said:
sorry probably covered 100 times, but how can u tell if engine is reverse or standard rotation when engine is out of boat. any visual signs>? would the crank post thread for pulley be left hand thread if reverse rotation? i dont know if i can spin motor, probably froze but not sure. thanks in advance
Click to expand...

Ayuh,... WHAT motor,..??
 
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russ67chevelle

Cadet
Joined
Jul 8, 2010
Messages
16
Re: standard or reverse rotation?

oh im sorry. boat is a 1987 powerplay with omc cobra chevy 350 engine...on manifold it says standard firing order. i pulled distributor and its gear is same as my pick up trucks.
 
Bondo

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
70,525
Re: standard or reverse rotation?

russ67chevelle said:
oh im sorry. boat is a 1987 powerplay with omc cobra chevy 350 engine...on manifold it says standard firing order. i pulled distributor and its gear is same as my pick up trucks.
Click to expand...

Ayuh,... On a SBC, the cam turns the same way anyways...
The timing chain is replaced with gears, so only the crankshaft turns backwards...
 
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