Volvo Kad32 problem

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ruddillo

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Hi, i write from Italy, my boat has 2 volvo penta kad 32. At wot the left engine reaches 3800 rmp, the right engine reaches 3500 rmp, and when i add fuel, in the left tank i add 150 liters, while in the right tank i add about 180 liters.
what can be the problem? thanks
 
Hi

First of all welcome to the forum, although up to this moment you are probably wondering if anyone is going to reply to you.

The reason being is that you need to give more info for someone to be able to answer, such as is this problem new, has it been going on over a space of time, has any work been done recently to your engines, have you maybe dinged your props? I could go on but hopefully you now understand, we need more info!!

Looking forward to your reply.
 
Hi,
I take it these quantities of fuel are what was required to fill the tanks back up. So that the starboard engine that will only achieve 3500 rpm is using more fuel than the port engine that can reach 3800rpm.
As Peanuts says, this could be due to a damaged propellor, perhaps on the port side, so that engine spins upto it's max revs but does not produce its maximum power. The starboard engine, however is having to do more work than the port engine, so much so that it does not achieve its maximum revs, but still consumes more fuel bacause of the extra work it is doing.

It could of course be something else, we need more information.

Good luck

Eddie
 
thank you for your answer. The engines have 500 hours each, and every year a mechanic changes oil, filters, belts and all the parts that volvo requires. The props are in good condition with some little scratches on each.
I have made no works on the engines in the last 5 years only what i write up. Yes, The quantities of fuel are referred to full tank (i have two tanks one for each engine). I have this problem from 3 years but it seems to get worse in two last years.
(sorry for my poor english)
 
Hi
First of all, you say that you have had this problem for the past 3 years, getting worst in the last 2 - correct? But you have a mechanic service the engines but has not corrected the problem - why not?

I once sorted out a similar problem on a friends boat, the guy had spent lots on it trying to sort the problem out, but never getting it corrected. I said I would have a look, just viewing the engine over and noticed the locknut on the throttle cable was loose and had altered the amount of movement so was not getting full range at WOT, hence the drop in RPM. Nuts tightened in correct position, problem sorted, it was almost one of those 5 minute jobs!!

Now I am not saying that is your problem but start at the basics and work your way along.

I know you say the props just have some scratches on, could they be slightly deformed but not dinged therefore altering the pitch giving the RPM change. I don't know the boat you have but it could be worth swopping props and seeing if the problem moves.

Your English is far better than my Italian!
 
Hi Peanuts, the throttle cable check was the first thing i have done but that is ok: the right throttle cable goes at the end of his way and push the gas lever on my right engine at the end. I talked about this problem to a mechanic (not the one that serviced the engines) who said to me that could be a loss of compression in one cylinder. At that point i was scared and i not investigated further.
The boat is a Salpa Laver 31.5 (9.30 meters) a good day cruiser with a deep v hull
thanks
p.s. do you say that i can change my props from left to right and viceversa? i have the duo prop system.
 
Hi

I have to admit I have never heard of your boat so I looked it up, very nice.

Back to your question, yes you can change the props from one outdrive to another, I'm not saying that is your problem but it would be a good place to start, at least if it does not change anything you know it's not the props.

I know you said that the problem has been there for a while, did it happen suddenly one day or just get worst as time went on.

When did the boat last come out of the water for antifouling and leg maintenance?

Have there been any other problems with the engines?
 
my boat every year goes into the water in May and out of water in November.
In April, the shipyard apply antifouling on the hull and legs and then the boat is clean enough. I never had any other problems with the engines. So you think it is not a loss of compression in a cylinder?
 
I know you said that the problem has been there for a while, did it happen suddenly one day or just get worst as time went on.

Have you had any other problems with the engines?
 
Ok, so no other problems with your engines, but as I asked earlier, did this problem occur suddenly or have you noticed it getting worst since it originally happened.
I hope that request made sense to you.

If you set both engines at say 3300rpm, are both throttles in the same place or are they mis-matched?

Please reply with both answers - thank you
 
I noticed this problem since 2 years ago and i noticed it getting worst since it originally happened.
To get 3300 rmp in both engines the throttles are not in the same place , i have to push deeper the right throttle
thank you
 
Ok, so we both now know that the right hand engine is having to work harder to match rpm with the other engine so of course using more fuel.

I still believe in going back to basics and would still swop the props from one leg to the other, whether you wait until the boat is out for the winter lay up is up to you, I don't know how easy it would be for you to change them in the water, I can change mine OK but some boats are difficult due to large dive platforms etc.

I have not ruled out further work but not at this stage.
 
thank you again, i could try to swop the props from one leg to another whith the boat in the water if it is not difficult. (i never changed the props in a duo prop leg neither on ground)
 
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Update: I changed the props between the legs and nothing changed! there is still a difference of 250 rpm between left and right engine.
I tried also the max rpm at neutral and also the left engine reaches 4200 rpm and the right engine reaches 4000 rpm. Any ideas?
 
Not sure if outdrives run counter to each other, but we have the same problem on our Blythe Cat, yanmar 315hp diesels, through zf 2-1 boxes, in order to get counter rotation one box runs in reverse to go forward, thus there is a slight difference in the ratio, ZF confirm that no damage will be done but it is a bit disconcerting, and gives the same symptoms as you describe. Just read the latest post, if your down on revs unloaded then maybe you have restriction in the fuel supply, or the offending pump needs opening up a bit, try cracking the injectors one at a time and note if there is a difference in engine note, if one of them makes no difference then that cylinder is suspect, valve clearances are the first check, then the injector, and finally a compression test.
 
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Hi

Glad you got back with an update, pity it did not move the problem though. As you have mentioned you have a difference between high idles. It should be noted that offically they should be checked using a workshop tacho, not the boats tacho's. However you do seem to have a difference so there is something not quite there.

As mentioned by Omega2 there are items to check, I myself would be checking the valve clearances first, you make no mention of them in your previous posts, just changing filters etc. Then check the engines after the valves, if it is ok then thats it done, however next would be the injectors, checking the compression as each one is removed. My gut feeling is that a u/s injector would give you more than a 200rpm drop - I hope I'm right although I always stand to be corrected.

For info, the idle should be 675-725 and at high idle 4175-4225. Engine should be at operating temperature before checking the rpm's.

Please let us know how you get on.
 
thanks to everibody. At this point i have to wait until october when the boat goes to shipyard and then i can ask to the mechanic to check all the things you mentioned (valve, injectors, compression etc) I'll post again when i find the problem or for others suggestions
 
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