KAD 32 wont rev up

[CX54WEK]

Our KAD32 on A4 props revs upto 3800rpm in gear. Cruising is between 2800rpm and 3600rpm depending on weather and sea conditions this gives a speed of between 18 and 30 knots.

 

[Volvo KAD 32 tfft]

Our KAD32 on A4 props revs upto 3800rpm in gear. Cruising is between 2800rpm and 3600rpm depending on weather and sea conditions this gives a speed of between 18 and 30 knots.

Thanks for that info, what size and weight is your boat?

 

[CX54WEK]

Thanks for that info, what size and weight is your boat?

25ft about 2.4 ton dry weight.

 

[Volvo KAD 32 tfft]

25ft about 2.4 ton dry weight.

thats about 2ft longer and the same weight, mine is 9.5ft wide, Volvo have suggested A5 props, which is bigger A5 or A4?
thanks

 

[bammylovechops]

2900 is way to low at WOT, it should be 3700-3900 so you have a engine problem or its simply overpropped. In your profile you say you changed engines from a merc to the volvo, how did you figure out the gear ratio and prop dimensions?

Regarding the compressor issue, you say it cuts in as it should when you rev the engine out of gear, right? Does it also do this if you try several times?
If so you really need to look for the problem somewhere else, if it does not rev high enough in gear for the compressor to engage then its something else.

Hope it helps!

When people mention "WOT" , what do they mean, I'm a bit new

 

[Volvo KAD 32 tfft]

When people mention "WOT" , what do they mean, I'm a bit new

Welcome! it means wide open throttle

 

[bammylovechops]

Many thanks.

 

[[2068]]

thats about 2ft longer and the same weight, mine is 9.5ft wide, Volvo have suggested A5 props, which is bigger A5 or A4?

A5's are a bigger pitch than A4's.

 

[Volvo KAD 32 tfft]

New props on the way,

 

[Volvo KAD 32 tfft]

new props fitted, works fine,