Prop pitch

[Jegs]

Firstly, I have bought Mr Gerr's book &, if I live long enough, I hope to make full use of it. The supplied prop is 22x14 & I wonder if altering the pitch to 15 would make any discernible difference. What do you think?

Thanks,

John G

 

[Latestarter1]

Firstly, I have bought Mr Gerr's book &, if I live long enough, I hope to make full use of it. The supplied prop is 22x14 & I wonder if altering the pitch to 15 would make any discernible difference. What do you think?

Thanks,

John G

Are you making engine rated speed plus droop with 22X14, clean bottom and half tanks?

 

[Jegs]

Are you making engine rated speed plus droop with 22X14, clean bottom and half tanks?

Yes & I think it might over-rev if pressed. Thank you for your time.

John G

 

[Latestarter1]

Yes & I think it might over-rev if pressed. Thank you for your time.

John G

John

You cannot over rev a diesel engine, high idle governor cuts in at rated speed and progressively reduces fueling (governor droop) on mechanical marine engines droop is around 10%.

Marine engines have less droop than say automotive engines 15% droop as it gives more stable steady state governing at part load.

Give your motor the beans with clean bum and see if it meets spec rpm on data sheet WITH calibrated tacho, you will do it no harm if you can make rated rpm. Compare with 'high idle' test.

 

[jfm]

I wonder if altering the pitch to 15 would make any discernible difference.

14 -15 definitely discernible!

 

[Jegs]

Thank you LS1, I'll look into calibrated tacho: who said ignorance is bliss?

John G