Change rotation of engine?

[JFoshee]

I'm sure I'm not the first idiot to do this, but bought I've got a 305 engine out of a truck to go in my boat then realized my boat needs a counterclockwise rotation engine. I have the old engine that came out of it.What parts need to be changed to make a clockwise rotation engine( looking at back of flywheel) a counterclockwise rotation engine?

 

[Don S]

Re: Change rotation of engine?

Why do you think your original engine is counter clockwise rotation engine?

Mercruiser (MCM) engines are all standard LH rotation engines as viewed when looking at the flywheel. Only some inboard engines (MIE) are Counter rotating.

 

[JFoshee]

Re: Change rotation of engine?

I'll try to make this long story as short as possible. Bought boat at bargain price. Old motor had a cracked block. Previous owner purchased a used motor from chevy truck. He swapped the intake, flywheel, and the starter. Previous owner then lost interest in the boat. I decided before putting the engine in the boat I would spin it over and make sure the starter was good. Now to the point. When I spin over the Chevy 305 standing behind it, it turns to the left. Counterclockwise. I believe the normal rotation for this engine is clockwise rotation. If I turn the input shat on the Mercruiser drive, with the control in forward, it turns the prop in the counterclockwise direction.
In forward gear:
Normal chevy rotation is clockwise, standing at back of engine. Prop turns counterclockwise. (Looking at the prop from outside the boat facing it.)
Starter that came from old motor turns motor in counterclockwise rotation, which would make the prop turn in the correct direction, but motor is not set up to run this way.
I know this is confusing, but I wish someone would please help me make sense of this. If there is no problem I'd like to put the motor in and try out the drive this weekend, but if it is wrong i'd like to start tearing it down.

 

[proshadetree]

Re: Change rotation of engine?

I did this once but was years ago.The only thing I remember for a fact was the cam and the distributor was different.A reverse rotation distributor wont even fit in a standard rotation engine.The gear at lower drive is backwards.Now this was on an old 292 ford in a 60 something boat.

 

[Bondo]

Re: Change rotation of engine?

Normal chevy rotation is clockwise, standing at back of engine.

Ayuh,... That's just plain Wrong,...
Standard Chevy,+ for that matter Merc motors is Lefthanded, when viewed from the flywheel end of the motor...

 

[JFoshee]

Re: Change rotation of engine?

Thanks for your response. The manifold and distributor from the old engine are on the current motor. It looks to be bolted up correctly, no hammer marks on it. I need to change the cam for sure, or at least I would think. Anything else ?????.
I really thought this would be a more common problem. I must have the only boat that is counter clockwise rotation looking at flywheel. Just my luck.

 

[bigskiohio]

Re: Change rotation of engine?

so your drive is different not your motor?

 

[Don S]

Re: Change rotation of engine?

The manifold and distributor from the old engine are on the current motor.

If you was able to use the distributor from your old engine in the new one, then you have a LH rotation (Std.) engine.
The distributor gear is different on a RH and LH engine.
IF you want to know for sure, pull the timing cover. If you have a timing chain, then you have a Standard LH rotation engine. If you have 2 gears and no timing chain, you have a RH Counter rotating engine.
It sound to me like maybe the previous owner put on the wrong starter on the old engine, if that is what you are going by.

 

[ENSIGN]

Re: Change rotation of engine?

Dons right,normal rotation for a mercruser engine is counter clockwise when viewed from the flywheel.

 

[Bondo]

Re: Change rotation of engine?

I must have the only boat that is counter clockwise rotation looking at flywheel.

Holey Moley,... Dude,.... That's a Standard rotation Standard, Normal motor.....

 

[Don S]

Re: Change rotation of engine?

I think one of your biggest problems here is how you are checking engine rotation.
From the sounds of post #3, you are trying to determine engine rotation by what the drive does. That's just a bad idea.
I've had boats come in with counter rotating outdrives on them because the owner got a "Good Deal" on a used drive.

Several times you have mentioned you think that standard Chevy rotation is clockwise. It's NOT,
This is STANDARD FH ROTATION OF CHEVY ENGINE

 

[JFoshee]

Re: Change rotation of engine?

I would like to thank all of you who took the time to post to my problem and at the same time let me apoligize for wasting your time. After much deliberation, and tearing the engine apart ony to realize that it is a stock 305, I have decided that my engine is turning ccw which is correct. It took a while for me to undertstand, but it finally got through.
I have the engine almost completly apart now. I think I'll go ahead and work the heads and install new rings and bearings. Thanks again for those who tried to make me understand that what I had was right all along. :redface: