KAD 32 wont rev up

[Volvo KAD 32 tfft]

My Engine starts and runs fine, the compressor cuts in and out when it should, the boat cruises at 24 knots,
BUT now it has developed this;
after fishing on a wreck for an hour or two with lots of stop starts as you drift,
When we leave to go back the engine starts as normal but as i move the throttle forward it stays at around 14/1500 rpm, even if i push the lever to WOT posn it still wont pick up? it does this for about a quarter of a mile and then the compressor kicks in and away we go? any ideas/ thanks

 

[Chris_d]

Sounds like the switch on the throttle that engages the Supercharger clutch is a bit iffy.

 

[Volvo KAD 32 tfft]

Hi, Thanks for the reply, I was unaware that there was a switch on the throttle control? where will i find it?
cheers

 

[STEVEDUNSTABLE]

Hi, Thanks for the reply, I was unaware that there was a switch on the throttle control? where will i find it?
cheers

hi k32...you should find on the quadrant the the throttle cable pulls back, is a small plate about the size of a 2p coin bent virtical that presses lightly on a small micro switch at the rear or the quadrant....sorry about the discription but i dont know the correct terms or find a picture of it in a hurry ...hope this is of some help....

 

[STEVEDUNSTABLE]

hi K32 again....i think this is the part you are looking for. item number 46 http://www.marinepartseurope.com/en/volvo-penta-explodedview-7738870-27-3292.aspx

 

[Volvo KAD 32 tfft]

Steve, Thanks for your reply, unfortunately your pic wont open but got the general drift, so off to the boat in the morning and will have a look,

cheers Bill

 

[Peanuts]

"Sounds like the switch on the throttle that engages the Supercharger clutch is a bit iffy"

Why?

This is only applicable when you fully open the throttle and you say that your compressor is not working at it's usual position and also at WOT, then after a while it kicks in - correct?

Go back to basics - check the tension on the drive belts, especially the circulation (shorter) one - this drives everything!

Then report back to the forum!

 

[Volvo KAD 32 tfft]

Ok, All the belts were replaced when the engine was fitted so all new, i checked the tension all seemed good,
then located the micro switch, this has confused me ,
it has not got any form of button or tab on it to press or be pressed? and there is nothing broken off,
I notice a little tab about a centimeter square on the throttle lever/plate that stops about 2mm from the switch at WOT but does not touch any thing,
is this switch some sort of reed type magnetic switch?

 

[RIN]

Its a standard magnet proximity switch. When that tab gets near the switch it breaks the circuit which switches on the compressor. You can get it to do that by placing your keys in front of the magnetic switch. They cost around £170 so you need to be sure it is the switch. When the switch fails, the circuit is broken and the compressor will come on and not go off. If your compressor switches off at 2800 rpm, I don't think it will be the switch

 

[Volvo KAD 32 tfft]

excellent!! thank you for your informed and prompt reply,

now I am wondering if I should have changed the propellers, to suit my boat instead of using the ones that were on the drive, would 1ft either way really make a difference?

 

[volvopaul]

To test the throttle switch, place a screwdriver blade with the engine running at idle on the switch, if the comp cuts in its not the switch, if not it could be the black box relay thats failed, or check the push fuses on the electric box as a start.

 

[Volvo KAD 32 tfft]

To test the throttle switch, place a screwdriver blade with the engine running at idle on the switch, if the comp cuts in its not the switch, if not it could be the black box relay thats failed, or check the push fuses on the electric box as a start.

I carried out the screwdriver test on the switch, all good on and off as often as you like, Relay/s?, are you refering to the rotation speed relay or the other 12v 40A in the black box?
Under normal circumstances is there a control/relay/device that prevents the compressor from cutting in until the engine reaches 14/1600 rpm even if you push the throttle lever straight to WOT?
It did it again yesterday, the engine was warmed up we sat for ten mins or so and then started off I moved the lever forward slowly,
it got up to about 12/1400 rpm but no matter how far I pushed the lever forward the revs would not go any higher and the comp would not cut in,
so I took it out of gear and tried,
perfect! revved up to 1400 comp cut straight in.

Is it possible that when I fitted the drive I should have changed the props, if they were to big or too much pitch would they reduce the engine rpm to that degree?hmmm

Further info,
the fuel system is all brand new filters pipes tank etc, no air leaks,
as soon as the compressor cuts in the boat performs well 28 knots cruise at 22 knots at 2500rpm and has done several 8 mile runs since the installation at 22/24 knots.
thanks for your time.

 

[A_8]

"so I took it out of gear and tried,
perfect! revved up to 1400 comp cut straight in."

If it does this ok at all times I would look for the problem somewhere else.

Regarding the prop question, how much does the engine rev at 28knots?

Not sure how the compressor works on the KAD32 but on my 43's they cut in at a given rpm. If its the same on yours it may be that you have it overpropped and that the torque is to weak around 1200-1400 to actually increase speed quickly enough.
I had a AD31 (which I think is the same block that the KAD32 is based on) and the most annoying thing was how long it took to get my 22 feet boat on the plane, it would sit and struggle for a long time before the turbo kicked in.

 

[volvopaul]

I carried out the screwdriver test on the switch, all good on and off as often as you like, Relay/s?, are you refering to the rotation speed relay or the other 12v 40A in the black box?
Under normal circumstances is there a control/relay/device that prevents the compressor from cutting in until the engine reaches 14/1600 rpm even if you push the throttle lever straight to WOT?
It did it again yesterday, the engine was warmed up we sat for ten mins or so and then started off I moved the lever forward slowly,
it got up to about 12/1400 rpm but no matter how far I pushed the lever forward the revs would not go any higher and the comp would not cut in,
so I took it out of gear and tried,
perfect! revved up to 1400 comp cut straight in.

Is it possible that when I fitted the drive I should have changed the props, if they were to big or too much pitch would they reduce the engine rpm to that degree?hmmm

Further info,
the fuel system is all brand new filters pipes tank etc, no air leaks,
as soon as the compressor cuts in the boat performs well 28 knots cruise at 22 knots at 2500rpm and has done several 8 mile runs since the installation at 22/24 knots.
thanks for your time.

The other relay is the starter motor relay, the black box with the + and- hole is for fine adjustment to set the speed cut in/out of the comp clutch, the whole larg black box is the main high load relay for the comp clutch.

As your saying it works fine with the screwdriver blade then it should work with the throttle arm, on the arm you will see the piece of metal can be adjusted so open the throttle wide open, with the engine not running and check its on the switch, if not then adjust it till it does, then turn the ignition on but dont start the engine, you should hear the clutch cut in, if not try it with the engine running, another thing to look out for when the comp cuts in is voltage drop.

Look at all the gauges for that engine especially the rev counter, if the gauge readings and revs drop on gauges the coils are failing in the clutch.

 

[Volvo KAD 32 tfft]

28 knts is from the garmin gps, the rev counter shows 2900 rpm, the boat is always quickly up on the plane by about 15knts.

 

[Volvo KAD 32 tfft]

The other relay is the starter motor relay, the black box with the + and- hole is for fine adjustment to set the speed cut in/out of the comp clutch, the whole larg black box is the main high load relay for the comp clutch.

As your saying it works fine with the screwdriver blade then it should work with the throttle arm, on the arm you will see the piece of metal can be adjusted so open the throttle wide open, with the engine not running and check its on the switch, if not then adjust it till it does, then turn the ignition on but dont start the engine, you should hear the clutch cut in, if not try it with the engine running, another thing to look out for when the comp cuts in is voltage drop.

Look at all the gauges for that engine especially the rev counter, if the gauge readings and revs drop on gauges the coils are failing in the clutch

.

"adjust it till it does" At the moment it is about 2.0 mm from the switch at WOT, should it be touching the switch?

 

[A_8]

28 knts is from the garmin gps, the rev counter shows 2900 rpm, the boat is always quickly up on the plane by about 15knts.

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!

 

[volvopaul]

"adjust it till it does" At the moment it is about 2.0 mm from the switch at WOT, should it be touching the switch?

Yes it should touch the switch remember the screwdriver test, its doing the same job, you should also firstly check the the governor arm on the pump is making it all the way to place it in max throttle position, you will see a threaded rod with 10mm diameter nut on it, one is for idle the other max stop, make sure the throttle is making it all the way, if not then its cable adjustment not the kick down plate adjustment thats wrong, also 2800rpm is well down shouldbe 3800 from memory.

 

[Volvo KAD 32 tfft]

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!

I have to confess that i didnt,
my boat is 1ft wider and 1 ft shorter than the Sunseeker that i took the engine from, and about 350 kg heavier,
so i took a chance that it would be ok, I have contacted Volvo and they have said that the props should be A5,
so I am having the boat out on thrs to check,

 

[Volvo KAD 32 tfft]

Yes it should touch the switch remember the screwdriver test, its doing the same job, you should also firstly check the the governor arm on the pump is making it all the way to place it in max throttle position, you will see a threaded rod with 10mm diameter nut on it, one is for idle the other max stop, make sure the throttle is making it all the way, if not then its cable adjustment not the kick down plate adjustment thats wrong, also 2800rpm is well down shouldbe 3800 from memory.

Thanks for your time, I will check and adjust on Tuesday and report back.