Volvo Penta D6-350hp, revs jump from 1200rpm to 2000rpm !!!

[Bluerock0]

Both engines go in & out of gear fine so no problems there.

When accelerating the starboard engine revs jump from 1200rpm to 2000rpm but nothing in between!

When decelerating the revs come down equally.

To the knowledgeable out there this might be easy to diagnose.

All suggestions welcome

Paul.

 

[volvopaul]

Both engines go in & out of gear fine so no problems there.

When accelerating the starboard engine revs jump from 1200rpm to 2000rpm but nothing in between!

When decelerating the revs come down equally.

To the knowledgeable out there this might be easy to diagnose.

All suggestions welcome

Paul.

Sounds like prop slipping on hub if it’s a stern drive

 

[Advantage]

Ditto. Bad prop hub.

 

[Bluerock0]

The boat is a Sealine S42, the engines are on DPH drives, all four props are new

When accelerating the starboard engine revs jump from 1200rpm to 2000rpm which makes the boat kick on to the plane.

Its the engine that’s not responding, it’s as if the throttle has a dead spot.

Hope this helps.

Paul.

 

[julians]

The boat is a Sealine S42, the engines are on DPH drives, all four props are new

When accelerating the starboard engine revs jump from 1200rpm to 2000rpm which makes the boat kick on to the plane.

Its the engine that’s not responding, it’s as if the throttle has a dead spot.

Hope this helps.

Paul.

It could be the throttle potentiometer in the throttle lever. You could try swapping over the connectors on the bottom of the throttle lever, so that the left throttle controls the right engine and vice versa, and see if the problem moves engines. You'll probably have to recalibrate the throttles when you do this (not a big deal - takes 1 minute).

Might be worth trying a throttle recalibration anyway.

 

[volvopaul]

The boat is a Sealine S42, the engines are on DPH drives, all four props are new

When accelerating the starboard engine revs jump from 1200rpm to 2000rpm which makes the boat kick on to the plane.

Its the engine that’s not responding, it’s as if the throttle has a dead spot.

Hope this helps.

Paul.

Ah is this the one you bought from the Hamble ? At RK yard ?

 

[Bluerock0]

Julians; The throttles have been recalibrated to try & sort the problem but unfortunately it didn’t make any difference.

The potentiometer is a possibility but it’s not easy to get to the underside of the throttle housing, if I have to I will.

Volvopaul; No, I looked at the one on the Hamble but bought one in Portugal where I am now. Did the Hamble boat have issues as I nearly bought it.

 

[julians]

The potentiometer is a possibility but it’s not easy to get to the underside of the throttle housing, if I have to I will.

Worth a try I reckon

 

[Bluerock0]

We are going out on the boat tomorrow so will try swopping the plugs over on Sunday or early next week, I don’t want to get into bother with the family, potentially scuppering our plans!

 

[The Solutions II]

We are going out on the boat tomorrow so will try swopping the plugs over on Sunday or early next week, I don’t want to get into bother with the family, potentially scuppering our plans!

Hey there Capt. I’ve run into the same issue. How’d you end up solving for it?

please and thanks!

 

[novanta]

Maybe it's the manifold inlet pressure sensor.

 

[Bluerock0]

First of all apologies for the late reply, I haven’t been on here for a while.

Novanta, you must have had your weetabix, absolutely correct!

To cut a long story short it was a faulty pressure sensor that is located under the black engine cover on the port side towards the rear of the engine. It is an easy swop from the apposite engine to checkout.
Vodia didn't show any faults

Part is ; Pressure sensor 22320906 replacing 21385453 but please check yourself.

Hope this helps, let us know how you get on.

Cheers

Paul.

 

[novanta]