Yam 200 HPDI lost top 1k revs

[Andy]

Today we lost the top 1k revs on our Yam 200 HPDI. The boat will managed 40mph ... but usually hits 50ish.

Tomorrow I will check the plugs and coils. Any other ideas before I throw it at a service engineer?

Thanks

[codprawn]

I assume you have checked the prop and the drive leg?

Did it happen suddenly? Could be stale/dodgy petrol if the boat has stood a while.

Could also be the throttle cable has slipped.

[DGR]

Has it been left afloat for a while for the lurgs to grow on it? Don't underestimate their ability to hold you back...

[Roy Smith]

Checked the prop bush for slip ?

[codprawn]

Originally Posted by DGR

Has it been left afloat for a while for the lurgs to grow on it? Don't underestimate their ability to hold you back...

VERY VERY true!!!

prop slip would surely INCREASE the revs???

[Andy]

It's used regularly.
No marine growth.
Last week it was fine. Today its lost 1k revs.
The throttle is fully open in the engine, when the helm is fully pushed, no slippage.
Petrol is good, swapped to an external source to check.
Prop looks ok. Not sure if its slipping.
Engine sounds like its missing a cylinder, hence my checks tomorrow.

Any other ideas please shout ... I will check for them all again tomorrow, dont want to miss the P1 boats in Sunday, got to get it fixed!

Thanks for you suggestions

[Tony Hill]

Run the engine to warm, stop and take out plugs, look to see if any water on plugs - particularly bottom/lower ones. If water then its a new cylinderhead gasket. Better still test the pressure in the cylinder using a gauge. We have run HPDI's and have replaced cylinderhead gaskets on 4 or 5 of them at around 1200 to 1500 hours

Tony

[Andy]

We seem to have no spark on one cylinder. The plug and coil are fine, i swapped them out with no change. Does anyone know if this engine would not use this cylinder at idle ... maybe its not meant to be hot at these revs?
If there is no spark and its not the plug or coil, what could it be?

Tony we are on about 400hrs ... and I cant see signs of water.

I guess its in to the service centre on Monday, and we will not be going out to watch the P1 Boats tomorrow .... shame! Its the best boating weekend of the year, the solent looks amazing this morning!

[eupa]

There is a recall on this engine - to change the oil pumps. This for models prior to Oct. 2006. See my posts on this. -assuming your engine is a
a 2t V6 HPDI?. This should be under warranty.

sincerely

Jonathan

[jwalker]

Originally Posted by Andy

...If there is no spark and its not the plug or coil, what could it be?

This might help....or not. Ignition system.

So, trigger coil faulty > trigger to CDI wiring faulty > fault in CDI > CDI to ignition coil wiring faulty.