Carver Owners Forum

Hey all,

i have an 85 Mariner 36' and the starboard engine (454) engine is in need of some work or replacement.

What Generation of Mercruiser 454s were originally in this boat and what rotation direction does the starboard engine turn. is it the standard or opposite rotation engine on the starboard side?

Thanks
Abe

Welcome aboard Abe.

This link might help:

https://www.perfprotech.com/blog/boat-a ... ne-engines

In a straight shaft application, the starboard side is the counter rotator and the port side is the standard rotation engine. If the application has v-drives, the standard rotator will be on the starboard side. Of course this is providing nothing's been changed by a previous owner. If you can crank the engine over, see which way the engine turns over. The direction is determined by standing behind the engine, facing the flywheel and noting which way the flywheel turns. Your vintage has a counter rotator unless something has been changed.

What's wrong with the engine?

Thank you for the reply. Good info.
When i bought the boat, the previous owner said that it had thrown a lifter by being revved up to high prior to it being properly warmed up. so they rebuilt the top end. while putting it back together, they discovered that the exhaust manifold was cracked and stopped where they were. At this point, the intake manifold if off and the exhaust is off.
I'm debating on trying to put it back together or buy a new one to drop in. I dont have a lot of experience with engines and it seems no one will touch it half put together because they dont know what has been done to it.

Sounds a little suspect. They would have had to remove the exhaust manifold prior to removing the head(s). You would think they would have found the crack then.
Even so, if the heads are on you can do a compression test, this would give you an idea if it is worth putting back together for a try. If it checks out, and you put it back together and it runs fine great. If not your only loss is an intake and exhaust manifold gasket and associated labor.

A Mechanic (real engine guy ) should be able to look at what you have and see what they had replaced to at least verify the.....throwing a lifter ???? Even so after that you won't know what else is going on with that engine until it is running, maybe some water ingestion , who knows. As for the manifold part, why did they stop there, is the other engine ok ?.....will you be keeping the boat ?

I agree with Tom. I'd perform a few tests before condemning the engine based solely on what you've posted. Having said that, it does sound strange that they would have stopped work simply because of a cracked manifold. The expense of replacing a manifold that is already off isn't enough to walk away. Me thinks they discovered something else. In a high rev at idle condition, I'd also be looking for spun bearings, thrown rod, etc. There are many things that can come together to cause this such as detonation, worn bearings, grade of oil, oil starvation which could be a result of several things, lack of maintenance, etc. If there's something going on in the lower end, then it will mean removal, rebuild, or replacement. It may be worth getting an oil analysis, and finding out what the conditions were surrounding the over-rev; was it an accident or was there a pre-existing runability issue that the owner hoped would go away by revving up the engine, or was it a test after a repair.