engine rotation on 98 moomba outback

[spratt25]

Hopefully someone cab help me out. I have a 98 outback with a pcm seamaxx 5.7l that I'm rebuilding and cant figure out rotation of the motor called PCM the say its standard LH rotation as viewed from the flywheel but the firing order on the motor says 12756348 anyone have any ideas of which way it actually rotates thanks

[james yarosz]

As far as I know all inboard ski boats are lh rotation except for older Natiques.You could look at the prop on the boat and that will tel you which way it rotates.

[zabooda]

Confirmed. Counterclockwise rotation at the prop when viewed from the stern.

[spratt25]

Then why would the firing order on the motor be for a reverse rotation motor its stamped on the valve cover from PCM 12756348

[james yarosz]

It,s posible the motor could be RH rotation,or could just be the wrong valve cover.I know when an inboard is in gear going foward the transmission is direct drive.The prop has letters stamped on it telling if it is LH or RH drive.

[kaneboats]

When in doubt, send a PM to Engine Nut. He knows everything in this area.

Edit: Ah, whatever. I just sent him a PM. He has been golden when we need him.

[Engine Nut]

If you are rebuilding the engine and have it taken apart, you should be able to see if the engine uses a conventional timing chain or does it use timing gears. Typically right hand rotation engines used gears instead of chains so the cam and distributor would continue to turn the way it would on a standard rotation engine while the crankshaft turned clockwise.

[BensonWdby]

I have a 99 Mobius - which is basically an Outback - and it has an Indmar 5.7L engine with standard rotation. If you have a PCM - maybe it is aftermarket? Wasn't Nautique using PCM for a while and they are opposite rotation - correct?

[zabooda]

Moomba was using both PCM and Indmar at the time and the rotations were all the same for the Outback.

[SWGA Boater]

Look on your intake for the firing order. If it is a stock chevy manifold it will be stamped on the intake. Standard chevy engines are left turn. Firing order should be 18436572. My 97 outback is standard rotation, though it is a Mercruiser rather than PCM.

[SWGA Boater]

Look on your intake for the firing order. If it is a stock chevy manifold it will be stamped on the intake. Standard chevy engines are left turn. Firing order should be 18436572. My 97 outback is standard rotation, though it is a Mercruiser rather than PCM.

I meant to add... if the firing order you provided is correct, you do not have a standard rotation engine. You have a counter rotation or right turn engine.

If you have not broken the engine down, you can take the valve covers off and rotate the engine to see which order the valves are opening.

[spratt25]

Thanks for the help. The engine is completely torn down just got it back from the machine shop it does have a timing chain not gears but according to PCM they didn't use timing gears they said it would still be a timing chain even if reverse rotation but the guy I talked to there said according to model number and serial number it should be standard rotation but then I told him about the firing order and he said it could have just been the wrong one on the valve cover but I'm about 99% sure when I did the tune up on the last time I set it up with the reverse rotation timing orderand it ran fine. I'm really believing it's reverse rotation just everyone keeps telling me it should be standard but looking at the raw water pump impeller the fins are cupped like it would be rotating counter clockwise at the front of the motor which also leads me to believe its reverse rotation

[james yarosz]

Have you looked at the prop yet?

[spratt25]

Yeah I'm pretty sure its LH rotation and while I was putting the engine back together I found another PCM tag on the oil pan that says the firing order is 18436572 which is standard rotation just Dont know why there are two different tags on the motor both with the same model number and serial number just different firing orders

[spratt25]

Update the 383 is in and running great can't wait to get it on the water and the motor is standard rotation thanks for all the help