Marinette Boat Forum

Hey everyone. I am looking at a possible worst case scenario of a repower this spring. I am looking at reman engines instead of using the one I have because the cost is close to the same and I will be able to swap much faster. That being said I am 3 hours from my boat and am not positive on the rotation. I want to say its reverse but cant remember. Does anyone else know for sure if the 1970 single screw is reverse or standard?
Thanks, Mike

(pls don't rely on this answer because it's just a guess and I'm willing to be wrong in public) There doesn't seem to be the need for reverse rotation in a single screw. But it's def required for twins. If you're impatient for an answer you can google it

I had always thought the singles were all reverse rotators but I may be wrong. The firing order is a dead give-away. If you switch, I would thin you have to change the trans & prop as well or you will have to drive around backwards.

In most cases, not all, if your helm is on the starboard side, then you will have a reverse rotation engine.

There are a few exceptions:
There is certain gear reduction velvet drive that has the output opposite direction from the input.
A flywheel forward engine in this scenario would be standard rotation. This should not be a concern with chrysler engines as I don't think I have ever seen a flywheel forward chrysler.

Again, this is USUALLY the case, in MOST inboard boats. There are always exceptions though.

Evening guys,
My 72 28' single 318, helm on starboard side, is standard, rh rotation. (When the damn things running)
May be on the road to recovery, I'll let you know.
Regards to all,
Rockxx

A good example of engine rotation.

http://www.ebasicpower.com/faq/starterrotate.htm

Hope it helps.

bill

I agree firing order and the spacer under the distributor is a quick way to I.D. them not running.

Thanks everyone. I plan on heading up this weekend to see her for the first time since fall so I will know for sure then. The reverse rotation engine seems to be a little more expensive or take longer to get. I would just like to be able to get a full season in this year if possible with no issues . Things just seem to break on an old boat, I know you guys understand what I mean.

Like other have said, there are many ways that one can check what the rotation is, with the easiest being, just cranking it over. Rockxx, rh rotation is not standard, it is opposite rotation.

You have to be careful when using the term "standard rotation" in the marine industry. That term only came about when the automotive engines started to be marinized and was only used by rebuilders and such. The industry standard has always been right hand and left hand rotation as viewed from aft. This goes back to steam engines and direct reversing gas, oil, hot bulb and diesel engines where there was no standard rotation.

99.9% of engines go by the balancer end of the engine for rotation, and call clockwise standard rotation.

There are always exceptions, and back in the 50's and 60's there was alot of confusion.
Example, graymarine v8c and v8cf engines as well as the famed chris craft 327F and 327Q. One sits in the boat forward and the other is flipped around with the transmission bolted to the balancer end of the engine.

Makes for a fun time when trying to find somebody parts over the phone.