Volvo Penta 290DP gear ratio location?

[Ckale]

Where can I locate the gear ratio on a 1990 model VP 290 Duoprop?

Sorry, newbie here! gotta start somewhere

What should my WOT rpm's with a 4.3 gas engine? Im only getting around 3,000

I am running at around 4,000' elevation

Any suggestions for prop sizes? I think my boat is set up for sea level right now

And how do the volvo prop sizes work? for example, what is a B5 prop? I know the first letter is the material, and second is the pitch, but what is the difference between a b5 and a b6

Thanks in advance

 

[Don S]

Re: Volvo Penta 290DP gear ratio location?

If the drive is all original, the gear ratio should be on the drive ID tag on the upper gear box, just in front of the top cap.

The DuoProp props are not listed by pitch, because the front and rear props are different sizes and pitch and designed to work together. That is why they are listed by sizes between B1 and B8.
The change in rpm is about 200 to 250 rpm per size.
Since you are down to 3000 rpm max at WOT, you probably have engine problems. Did it run ok at one time, or is this boat new to you?

 

[Ckale]

Re: Volvo Penta 290DP gear ratio location?

The boat has been sitting in salt water, so its very hard to read the ID tag...Is there any other way to find this out?

the boat is new to us. According to my father (he drove it last) the most it would do is 3000. Motors seem to run fine though...nothing apparently wrong, we are very mechanically inclined.

the boat is a 27' Carver, weighing about 8,000lbs empty, with twin 4.3's and 290 duoprop outdrives

 

[steelespike]

Re: Volvo Penta 290DP gear ratio location?

At 4000 ft your down about 12% on power.And thats if the carbs have been rejetted.
If the boat has been sitting in salt the bottom is probably fouled.
I think the best way to be sure of the ratio is to remove the plugs mark the pulley or something on the motor
and mark a prop. Rotate the motor and count revolutions to rotate prop once.Don't know if the duo prop will require holding one prop
to get an accurate count.Perhaps mark both props.As you may have discovered Volvo loves mystery.
You might go to the Volvo section and ask about prop nomenclature.While it is a prop question it is also a very Volvo
question.I think your more likely to find Volvo knowledge in the Volvo section.Tell them I sent you I'll take the heat if any.

 

[Don S]

Re: Volvo Penta 290DP gear ratio location?

Both props turn the same speed, just opposite directions. On a 4.3, you should have a 2.30:1 gear ratio, so you would need to turn the engine 2 - 1/3 turns to turn the prop one complete revolution.

 

[Ckale]

Re: Volvo Penta 290DP gear ratio location?

Im not sure if it sat in salt water for a long time, or if it had an electrolosysis problem. The previous owner said it was a 95% fresh water boat.

Anyways, I will go to the volvo section and inquire about props.

Thanks for your help!!!