Mercruiser Outdrive Has To Be Geared Wrong

B

BarrenRiver

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Throw this out and see if I am over looking anything........I finished out a houseboat which I bought last year at auction when a houseboat company went out of business. I moved it to another houseboat manufacturer to install fuel tanks, generator engines, outdrives, etc etc

It'S 16'X86, with 4.3L engines installed with Bravo II outdrives. It was splashed in mid summer this year.

Upon splash the port engine would over rev at wot, the starboard ran at normal wot rpms.

I had right and left hand props installed and the Mercury left hand was on back order when splashed with an after market prop in its place...thinking it might be the prop a Mercury left hand prop was rebuilt and installed, it kept it from over rev but still out of range.

The Mercury left hand came in and was installed which caused the over rev problem again.....NOW not really having a baseline to go on, I had two good props off my old boat which I knew turned the same and had them put on. Same result, starboard in tolerance and port over rev.

I am thinking that Mercury geared the outdrive different than what was ordered and what the paper work calls for and what the outdrive says

According to Mercury via the houseboat company which finished it out, that could be the case as he says all gears come down the same line and the wrong one could have been installed....wtf kinda of quality control is that?

We were told to pull the boat, take off the outdrive and turn the shaft and count the prop turns and if it was wrong they would send a new outdrive. When told you just don't run this up on a trailer and the shipping on the outdrive would be cheaper than a second pull they are sending a new outdrive.....

We plan on putting the boat on the trailer backwards and just up the ramp enough to change out the drive and hopefully that will be the cure....anything else you can think of??
 
I might have bad news for you our marina has had a rash of bad builds from Mercury. We just found out Merc is outsourcing most of it's product line.
We had 3 bad engines in a row that had to be sent back to the factory from a single speedboat. These were 502 special builds (the supercharged version).
I have a buddy who bought a 300 hp Verado he has had nothing but problems with it and it's only a year old. He is about ready to give up on boating.
I'm not sure what's going wrong but I believe there is little if any quality control going on with Merc.
Bill
 
There's a chance it's the coupler. When you pull the drive, put your hand in there and feel the coupler. You may be able to feel it now by putting your hand down behind the bell housing. The coupler is bolted to the flywheel. feel for any dingle berries from the rubber donut.

What size props do you have.
 
What is the RPM delta between the two?
I agree with Charlie, only place for slippage as the culprit would be the coupler or the prop hub.. You eliminated the prop hub with all the different props...
If you are up on the trailer.. Besides counting, you could swap the drives/props and see if the condition follows the drive.. BII are not directional..

John
 
I can't recall the prop size and pitch off the top of my head but will go to the boat later today and check and also will check the coupler...
 
You could put the outdrive in gear, pull the plugs, and rotate the engine by hand. But, since they are already shipping a new outdrive, it is a moot point. I would, however, compare the new with the "good" one to make sure they match.

I have Bravo IIs on my Jamestowner. And, I know the hassle of pulling a houseboat.

Good luck.
 
Props are 19.5 x 13 The coupler appears ok....The plan is to put the boat partially on the trailer backwards and pull out of the water enough to change the drives ...
 
The only other place for slippage is the cone clutch being all worn out.

Is there slippage in reverse? Maybe clutch needs adjustment.
 
I really do not see how you are going to be able to back it partially onto the trailer without the drives/props hitting something on the trailer. I have moved houseboats four different times with four different movers and have not seen a houseboat trailer that would allow you to do what you are talking about. Take some pics if you get a chance, I would like to see how they do it.
 
Looking at the 13" prop pitch again, If you have 2.2:1 gear ratio I guess it's possible to over rev the engine easier.
 
The Issue Has Been Resolved!!!!!

And it wasn't the outdrive..........after getting the boat on the trailer backwards and pulling it onto the ramp just enough to take off the drive, it was checked and found to the be geared properly. Scratching their heads the houseboat manufacturer that finished this boat out for me NOW checks the programming on the electronic shifters and throttles and find that side was never set up.....wtf From day one I ask them if they had been checked, on the final set of props put on a friend of mind also ask the same question.....

I have set up and adjusted the Mathers Controls before but didn't look at these assuming they had..and said they had. So with heads between hanging low they have a new bravo II in an unopened box, had a crew of 4, along with tractor trailer rig on the ramp a half day..not to mention 3 trips changing props in the water .and it comes down to programming the controls....
 
Hmmmm Programming the controls??? It seems that your capability of over revving one side may indicate that both sides may be under propped - WTF
 
Many years ago I bought a new boat with Volvo outdrives.
first time I took it out same problem. Great torque but over reved.

turned out someone had put drivrs for 4 cylinder engines on 8 cylinder engine.

George
 
If the WOT RPMs are controlled by the electronics instead of the maximum capability of the engine you are NOT getting optimum performance out of your setup.

Diesel engines are set up by adjusting the governor to a RPM specification provided by the manufacturer. I like to adjust "HIGH IDLE" 100 RPM higher than spec then prop the boat to manufacturers rated WOT spec RPM.

Suggest you do likewise.
 
quote:
Originally posted by OLD HOUSEBOATER

Hmmmm Programming the controls??? It seems that your capability of over revving one side may indicate that both sides may be under propped - WTF

Click to expand...


My thoughts as well.

I would think you will end up burning a lot more fuel than necessary as well as putting a lot of unnecessary stress on the engines.
 
David

If the RPMs are choked off with the controls he probably isn't getting the best economy or performance, but he's probably not hurting the engines.

Rodney
 
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