Under performing Kad32

[Derek.J.W]

Hi, I have a Rinker 260 Fiesta Vee powered by a single Kad 32 and a DP 290 Duoprop stern drive,
The original props when i bought the boat were B5s these were in a poor state, as was the rest of her, i have spent much time effort and of course money bringing her back to life,
i replaced the props with a pair of Michigan B5s
Boats in the water and she struggling to get to the 1500rpm to bring in the supercharger, Are these props too much for the Kads 170bhp.
Also, when the charger does spool up it cuts out at 2500rpm as it should but the Turbo doesnt always cut in, she drops off the plane, the charger cuts back in when the revs drop and the process starts all over again, it hit and miss, its got me baffled.
Any tec wizards out there with some steerage?

 

[Momac]

B5 props doesn't seem right.
My Sealine S23 with kad32 had A4 props

 

[ChromeDome]

As the original props were B5 too, they would have produced the same problems. Did they - or were too damaged to tell?

Previous thread about the subject:
Replacement after-market props to replace Volvo Penta duo props

 

[Derek.J.W]

Ahh right, that could explain why she's struggling to wynd up, i went off what was already fitted, once she's on the plain she's doing 20knts at 3000rpm, getting her there's the problem, I'm still looking to boost low down power from the engine, otherwise I've wasted over £500 on props
Thanks for the reply, much appreciated.

 

[Derek.J.W]

As the original props were B5 too, they would have produced the same problems. Did they - or were too damaged to tell?

Previous thread about the subject:
Replacement after-market props to replace Volvo Penta duo props

Too damaged to tell, never had her out until much work and new props fitted.

 

[ChromeDome]

Good dealers offer to switch props after testing, until you get it right.
Provided they're returned in as-new condition.

 

[ChromeDome]

BTW: Performance improvement can be had by removing dead weight from the boat. Very efficient, helps mpg - and FREE

 

[SC35]

It's also worth removing the exhaust elbow and having a visual check of the exhaust side of the turbo.
Excessive vane tip clearance or corrosion of the housing will be working against you.

 

[Momac]

kad32 definitely requires a series duo props

 

[Derek.J.W]

Actually its a KAD 32 P, The supercharged version, if I'm not mistaken there's a Kad 32 which isn't supercharged, The only reason i think this is when you look to buy parts,
Thanks for the info Martyn

 

[tico]

Think you may be thinking of the AD31 (non supercharged)...150hp

The 'K' stands for 'Kompressor' = Supercharger

 

[Derek.J.W]

BTW: Performance improvement can be had by removing dead weight from the boat. Very efficient, helps mpg - and FREE

I don't carry a lot, she's about 3 tons fully fueled, i removed the water tank and fitted a smaller one to at least reduce some weight, thing is, if im on my own or with two pals which are over 6ft and not exactly light it makes no difference,
Its just the struggle to get to 1500rpm,
Martyn mentioned taking off the exhaust elbow and cleaning / inspecting it, thats now on my list, as is an aftercooler clean.
Thanks for the reply, much appreciated.

 

[Derek.J.W]

Think you may be thinking of the AD31 (non supercharged)...150hp

The 'K' stands for 'Kompressor' = Supercharger

Nah i had an AD31, pretty much the same engine but no charger, no mention of a K but i know its the Kad32 P and when looking up parts its said the P was the supercharger Kad32,

 

[SC35]

Nah i had an AD31, pretty much the same engine but no charger, no mention of a K but i know its the Kad32 P and when looking up parts its said the P was the supercharger Kad32,

I don't think that's correct.
If it doesn't have a supercharger, it is something else, not a KAD32.

Many parts are common to AD31, so the confusion could be due to the way that the parts website has been built.
Also some of the newer "D" series engines have both supercharger and non-supercharger (for shaft drive) versions, so maybe that choice was put in for all engines.

 

[Derek.J.W]

Mine's a Kad32 P, Supercharged / Turbo charged, i did notice many of the AD31 parts fit the Kad 32, it did confuse me when it said the P was the supercharged version, i thought all Kad32 engines had this set up.
I have a few things to try, the fact she's very slow to pick up and the fact the turbo doesnt always kick in at 2500 are my main concerns, once she's going she sings.
Thanks for the replys

 

[Momac]

Actually its a KAD 32 P, The supercharged version, if I'm not mistaken there's a Kad 32 which isn't supercharged, The only reason i think this is when you look to buy parts,
Thanks for the info Martyn

All kad32's are supercharged and turbocharged,
The P is irrelevant really but probably means Pleasure use as opposed to commercial use. But there is only one version of a kad32 as far as I know.

 

[QBhoy]

Hi. If I was a betting man…I’d have a wager on the odds that this boat may not have had that engine originally perhaps ? Instead she may have had a GM v6 or v8 Petrol. Perhaps meaning that you have still, a 290dp drive with a gear ratio suited to the original and very different rpm range of the previous engine ? The mention of B5 props might further shorten the odds perhaps.
Original installed engines like the kad32 or similar, would almost always have had a outdrive geared and propped to suit the diesel’s very different means of power delivery, in terms of power made through the rpms. Not exclusively, but certainly commonly, they’d have been propped with A series props too.
You might be lucky and get away with a prop change just…to allow the diesel to play ball…the mention of the supercharger not being relieved by the turbocharger suitably, may indicate turbo issues perhaps…but given the miss match of gearing and props currently, could just be the case that it’s just too much an ask for the current power plant to put her power to the water well.
If I’m wrong…then ignore all of the above…haha. But there is a fair old chance I’m right though. All the best

 

[Momac]

Hi. If I was a betting man…I’d have a wager on the odds that this boat may not have had that engine originally perhaps ? Instead she may have had a GM v6 or v8 Petrol. Perhaps meaning that you have still, a 290dp drive with a gear ratio suited to the original and very different rpm range of the previous engine ? The mention of B5 props might further shorten the odds perhaps.
Original installed engines like the kad32 or similar, would almost always have had a outdrive geared and propped to suit the diesel’s very different means of power delivery, in terms of power made through the rpms. Not exclusively, but certainly commonly, they’d have been propped with A series props too.
You might be lucky and get away with a prop change just…to allow the diesel to play ball…the mention of the supercharger not being relieved by the turbocharger suitably, may indicate turbo issues perhaps…but given the miss match of gearing and props currently, could just be the case that it’s just too much an ask for the current power plant to put her power to the water well.
If I’m wrong…then ignore all of the above…haha. But there is a fair old chance I’m right though. All the best

Could be so.

 

[QBhoy]

Could be so.

Better than average chance of it. Given the boat type and props mentioned.

 

[Momac]

Its been a long day . If the leg gearing was for a higher revving petrol engine would the diesel not rev freely but the boat make little speed?