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Questions regarding 84 aft cabin

Posted: March 19th, 2021, 5:04 am
by Dad Joke
Does anyone here have a spec on the transmission used on this boat and a link to an online shop manual for them?

Which engine spins in the conventional direction (same as automotive application)? and which spins opposite?

Thanks.

Re: Questions regarding 84 aft cabin

Posted: March 19th, 2021, 6:12 am
by Phrancus
Welcome, it will help if you describe more specific what your boat is equipped with as there were variations in layout, engine(s), drives and so on.

Re: Questions regarding 84 aft cabin

Posted: March 19th, 2021, 7:02 am
by Viper
Hi Dad! if it's a straight shaft application (no V drive), the standard rotation engine will be on the port side and the counter-rotator on the starboard side.

Are the transmissions missing? The boat model and engine info would help. Hopefully a member with the same model will chime in with the info you need. Also a call to Carver with the hull number will lead to what she was equipped with when she left the factory. It's likely a Velvet Drive 72C, but gear ratio is important.

Re: Questions regarding 84 aft cabin

Posted: March 19th, 2021, 8:21 am
by denders
There may be a plate on the transmission - something like this from our previous 83 carver

Re: Questions regarding 84 aft cabin

Posted: March 19th, 2021, 8:28 am
by Dad Joke
It has 2 Crusader 270hp 350ci engines. Straight drive, not V-drive.

The reason for all these questions is because the port engine is seized. The engine that turns opposite from conventional will be more expensive to replace. It sounds like the port engine would be the less expensive one to replace, based on Viper's response.

Re: Questions regarding 84 aft cabin

Posted: March 19th, 2021, 11:40 am
by RobGunn
I have a 1990 aft cabin 3607 with twin Mercruiser engines 7.4L (454 ci). Both of my engines rotate the same direction, the propeller rotation on one side is change by the transmission. You could take a look at the order fire of the spark plugs to see if you engines are the same or if one is built to run opposite.

I do wonder that even if you do have opposing engines, I wonder if you could simply use a normal rotation engine and setup you transmission to run backwards? Maybe someone else on the forum could answer that? Basically replicate what my boat is doing?

Re: Questions regarding 84 aft cabin

Posted: March 19th, 2021, 12:50 pm
by Cooler
Dad - the spec plate on your engine should have a model number on it. The model number has a R or L listed on it. R = right, L = left. Left turning engine is normally on the starboard side. Model looks like "CM350L". If you have the original warranty card in your possession, the model numbers are also listed there. Hope that helps. 8-) er

Re: Questions regarding 84 aft cabin

Posted: March 19th, 2021, 1:50 pm
by km1125
you can sometimes also look at the timing marks to see which direction is "BTDC" and "ATDC" to determine which way the engine rotates. These pics are for a 454 ci Crusader, but other engines are similar.

crusader_timing_marks.jpg

Re: Questions regarding 84 aft cabin

Posted: March 19th, 2021, 4:25 pm
by Viper
RobGunn wrote:Source of the post I have a 1990 aft cabin 3607 with twin Mercruiser engines 7.4L (454 ci). Both of my engines rotate the same direction, the propeller rotation on one side is change by the transmission......
Pretty sure that's not the case on an '84

RobGunn wrote:Source of the post.... I do wonder that even if you do have opposing engines, I wonder if you could simply use a normal rotation engine and setup you transmission to run backwards? Maybe someone else on the forum could answer that? Basically replicate what my boat is doing?
Doable with more modern transmissions but not of that era, that's why the counter rotating engine was used.

If there's a re-power in order, go with standard rotating engines, and newer tannys that will run under full load in either direction.

Re: Questions regarding 84 aft cabin

Posted: March 21st, 2021, 11:25 am
by bud37
Dad Joke wrote:Source of the post It has 2 Crusader 270hp 350ci engines. Straight drive, not V-drive.

The reason for all these questions is because the port engine is seized. The engine that turns opposite from conventional will be more expensive to replace. It sounds like the port engine would be the less expensive one to replace, based on Viper's response.


Welcome Dad.....can I ask you a question ?......Let's say all is well and this boat passes the hull and deck survey with flying colors.....now the big question, how much would you consider spending on the mechanical ++ refit and how long will you keep the boat after the refit ??

Reason I ask ,if it were me considering the one engine is locked and there is no telling what the shape of the other or both trans are , I would do a complete both side repower with the trans to upgrade to newer reliable equipment, but only if you are going to keep this boat for a fairly long time. Yeah I know it is easy for me to spend your money but it is just one thing to consider along with what the finished product is actually worth on the market should you change direction.......good luck going forward, these adventures can be alot of fun.