Penta D1-30 with 130S saildrive low RPM

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Kemp

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Hello, I have almost new (about 40-50 hours) Penta D1-30 with 130S saildrive. Full throttle should be 3200RPM, but engine produces just 1900-2000RPM. At neutral engine's full throttle reaches 3500RPM. Oil level in both engine and saildrive are normal. No leaks, no strange sounds. Please help.
 
Kemp said:
Hello, I have almost new (about 40-50 hours) Penta D1-30 with 130S saildrive. Full throttle should be 3200RPM, but engine produces just 1900-2000RPM. At neutral engine's full throttle reaches 3500RPM. Oil level in both engine and saildrive are normal. No leaks, no strange sounds. Please help.
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Has it been like this from new? If so, sounds like it's over-propped. If not, sounds like there's fouling of some sort. As Yotter said, more info needed.
 
When the engine was commissioned there should have been a check that it achieved at least 2900 otherwise it should not be signed off and the warranty activated. So, if it has never achieved that the installation is wrong, probably the prop is too big. However only getting 2000 suggests the prop is very much oversize, as much as 3" too much pitch and would be surprising if that was the case. You do not say whether it is a new boat or a re-engine, but usually with a new boat the builder gets the prop spot on and it is only if a non standard prop is fitted afterwards that there is a possibility it is wrong. With a new boat the onus is on the dealer to ensure the engine achieves the correct revs. On my new boat (with the same engine) we did this on the sea trials before handover. It was particularly important because I had fitted a non standard FlexoFold prop which achieves 3100 and 7.4 knots.

So, if the low revs has been there from the start the responsibility is with whoever installed and commissioned the engine. If it has developed then it is probably a fouled prop. whichever its is needs urgent action as you will wreck the engine running as it is for any length of time.
 
pvb said:
If the exhaust were blocked, is it likely that it'd be able to rev to 3500rpm in neutral? (I'm ignoring the suggestion that the exhaust might block in only 40-50 hours of running.)
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Sorry, some missed the low hours.
 
What would be the effect of a fault ( fuel or injector perhaps ) that resulted in it running on only two cylinders?

Would it still rev to full revs in neutral ?

Would there be other obvious symptoms?
 
All we know is that either the engine is not developing power, fuel supply problem? Airlock perhaps
Or the prop is taking too much power to turn, oversized as stated.
In either case free revving in neutral would be possible.
 
As others have said, I'd suspect a fouled prop. I was amazed at how much difference it made cleaning up the prop after a winter in the marina. I hadn't realised the problem that could be caused by a fouled prop and had struggled across to Mallorca from Barcelona getting little more than 2000 rpm from the engine at full throttle. I was left puzzled by the problem until someone asked me to dive on his boat and replace the anode and scrape his prop: this prompted me to look at my own prop which was heavily fouled...... A quick attack with a scraper and things were back to normal.
 
Volvo MD2030 on a friend's boat. Able to reach 3350 at full throttle. We were coming out of the marina (some months ago) and the boat was able to reach only around 2300rpm maximum. He dropped anchor, dive with a knife and some water parer and cleaned the prop. Right after this the engine was able to reach again the 3350 rpm. I was really amazed!! And what suprised more was the fact that the hull was relatively clean and only the prop was fouled.
 
The proppeler is 3 blade Volvo 17x12. Boat is second hand, so I have no details on commisioning. Hull was cleaned back in April by diver.
 
Kemp said:
The proppeler is 3 blade Volvo 17x12. Boat is second hand, so I have no details on commisioning. Hull was cleaned back in April by diver.
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What boat is it? That is a very common size fitted to many Bavarias for example with that engine. So, doubt anything is wrong with the propeller size. Did your diver clean the prop in April as everything points to a fouled prop, either growth or something wrapped around it. Time to send a diver down again to check.
 
Strange.

Can you swim under the boat and spin the prop with the engine in neutral? It should spin quite freely in your hand but not so free that you can spin in and it will continue for more than a quarter of a rev or so once you let go.

Richard
 
RichardS said:
Strange.

Can you swim under the boat and spin the prop with the engine in neutral? It should spin quite freely in your hand but not so free that you can spin in and it will continue for more than a quarter of a rev or so once you let go.

Richard
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Thanks. Will check this tomorrow.
 
RichardS said:
Can you swim under the boat and spin the prop with the engine in neutral? It should spin quite freely in your hand but not so free that you can spin in and it will continue for more than a quarter of a rev or so once you let go.
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Checked. There is no difference engine in neutral vs engine off. Prop spins smoothly and feels like spinning car wheel.
 
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