VP DPSM outdrive

[robwny]

The tag on outdrive says 1.95 gear ratio. Before I bought this could someone have put a different lower or upper gear to go with existing 1.95
To make the drive act like it has a 1.78 ratio

 

[89retta]

What make and size of boat ? Also what size engine ? And what makes you think that ?

 

[robwny]

It’s a 30 foot boat with twin 5.0 Volvo Penta and come to find out last year one of the outdrives had a different gear ratio.
I took care of that problem and now this one’s doing the same but not as bad so I’m just trying to figure out if somehow even though the tag on the Volvo Penta outdrive says 1.95 could somehow somebody mix a upper and a lower with different gears that’s what I’m trying to find out
Is that possible

 

[robwny]

At full throttle getting on plane it falls on its face everything else checked out just like my out drive last year

 

[Maclin]

Yes, it is possible. When did you buy the boat? Your posts are a little murky on the timeline. Are you saying you bought the boat after the outdrive change, and there was a period of time after the changeout that it was not in your possession?

Seems like both drives would at some time have had the same ratio. Then one got changed out to a known 1.95 ratio it seems. Was the other drive then checked to validate what the actual ratio was for it? And how did the boat perform right after changing just the one drive? I mean, a drive would not just start acting like a different ratio all of a sudden. Maybe the engine is not up to snuff.

Did this boat used to have Diesels, and got changed out to Gas engines?

 

[robwny]

No I bought the boat last year without a survey I know foolish and I could not get the Port motor working very well and it up being The outdrive had a 1.78 Gear ratio which is wrong.
That has been replaced with a 1.95 outdrive it works fantastic. The Starboard motor they gave me No problem is that I knew of last year. Now is giving me the same symptoms as last year the tag on the Outdrive says 1.95.
it definitely does not do it is bad as the 1.78 did last year so I’m wondering if someone could put a different lower end gear set in it. So far everything in the motor in fuel brand new fuel pump’s everything is been scanned checked this is why we’re going about this switching the drives. My question is good they put a 1.78 lower unit in it and would that make it like a 1.85 ratio with the top gears I’m just guessing at this

 

[BRICH1260]

The only way of knowing is to pull the upper gears and count the number of teeth. I`d bet that the tagging is the correct ratio. It would be a lot of trouble to swap out just the gears, most people just replace the entire unit. You might try experimenting with the prop pitch to see if you can resolve your planning issues.

 

[Maclin]

Seems to me that looking at the tachometers at speed should show if the engines are close to being in synch?

As for the rest of it, I think the lower on DP's are all the same, and when combined with whatever was in the upper gives the final ratio. This may not be correct, so reader beware. If your tachometers are not in synch (and they work correctly) then you really need to verify both drives are the same right now by actually physically counting rotations at the driveshaft (or engine) and prop. If they are then look at the engine tune state.

Good luck!

 

[cnotecherry]

There are only two different upper gear sets and 3 different lower sets 1.68, 1.78 and 1.95 have the same upper set 22/23 tooth count and different lower sets 2.11 and 2.32 are 21/26 tooth count for the upper set so if you had wrong upper set you would be a higher ratio you can very easily put a different lower gear housing on though and it could make a 1.78 or 1.68 it is very easy to test your ratio have a guy by your props and put a big wrench on the crank while in gear turn over motor slowly CLOCKWISE keep track of where you started and were you stop the guy at the props tells you when the props have done one complete rotation then you should be able to figure out your ratio by how many time you're engine turned marking out the harmonic balancer makes it easier to know for sure

 

[muc]

Swap the drives from side to side and see if the problem follows the drive?

 

[robwny]

There are only two different upper gear sets and 3 different lower sets 1.68, 1.78 and 1.95 have the same upper set 22/23 tooth count and different lower sets 2.11 and 2.32 are 21/26 tooth count for the upper set so if you had wrong upper set you would be a higher ratio you can very easily put a different lower gear housing on though and it could make a 1.78 or 1.68 it is very easy to test your ratio have a guy by your props and put a big wrench on the crank while in gear turn over motor slowly CLOCKWISE keep track of where you started and were you stop the guy at the props tells you when the props have done one complete rotation then you should be able to figure out your ratio by how many time you're engine turned marking out the harmonic balancer makes it easier to know for sure

On a Volvo Penta the sea water pump sits on crank how would I turn it over ?

 

[cnotecherry]

You would have to pull the water pump off the balancer its 3 hexs bolts