Bukh 20 cut out

[chriscallender]

Hi

Yesterday when I was dropping someone off at Gunwarf Quays my usually reliable Bukh 20 cut out when I went into neutral in preparation for going astern, causing me to "arrive" at the pontoon rather faster than I had been planning - no harm/damage done though.

The engine restarted fine, and idled OK so I decided to head back to my mooring. On the way there I decided I better see whether the engine was OK, so went to neutral and it cut out again. Again, started instantly without any trouble. So I picked up the mooring very slowly and cautiously - this time the engine kept running fine, so when I was safely tied up I went forwards and astern and played around a lot with the throttle, not able to make it fail.

The other thing that I have always noticed about this engine, and it seemed even worse when it was having the problems yesterday was that it is very slow to pick up revs and respond to the throttle. I believe some part of that to be due to the prop - its definitely overpropped with a 16x13 prop (on a Seal 28) when most others seem to go with 16x10. So that was on the plan to be repitched - handling is a bit of a sod when you can't get the revs on quickly. Now though I'm wondering if there is a contribution to this problem from the engine as well, as it definitely seemed worse yesterday afternoon.

Both fuel filters were changed at the start of the season and the fuel in the bowl appears to be clean. Air filter was also cleaned then - but I haven't checked it recently. The fuel tank was nearly completely full, so I shouldn't have sucked any crap from the tank up - although we had come in from a fairly brisk sail and it was probably stirred up a good bit.

I plan to replace the primary fuel filter now as a precaution, and if its dirty I'll also replace the fine filter. I wondered if anyone has any ideas about what is going on with the engine -there is a paranoid part of me that is worried about it being something serious now - think I'd better have an engine servicing/maintenance day over the bank holiday weekend :-(

Any ideas? Could it be that I am getting a bit of air in the fuel lines somewhere?

Chris

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[30boat]

You may have something wraped around the prop .

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[chriscallender]

That thought did go through my mind as well. Will get my snorkel out next weekend and have a look.

Chris

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[neil_s]

My Bukh DV20 did that once last season. I put it down to an over-reaction of the governor when throttling back after running hard for some time. It also re-started without problem, but gave me a fright at the time. It has behaved OK since. I also have a Seal 28, and my prop is a 16X12 two bladed (original fit, I think). Remember the engine has a massive fly-wheel and can't change speed very quickly, anyway. The Seal 28 also has a bit of a problem with the propellor aperture being too small which causes cavitation on the propellor. 20HP should be good for 6 knots, but I don't get anywhere near it!

Cheers! Neil (No 27, Andiamo of Exe)

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[chriscallender]

Thanks for that Neil - I had indeed been running hard as my friend had a plane to catch. We were making for Portsmouth to put him on a train to London but the tide was starting to turn.... anyway he got to the airport 1/2 an hour early, so there was no need to worry ;-).

With clean hull I can make 6 knots maybe even 6.5 on the Stowe log which I trust more than the NASA, but with the forest that has grown in all the sunshine of the last month or so, more like 5 now. So perhaps no rush to repitch the prop if 16x12 was the original fit.

Anyway I'll check the prop and the air + fuel filters before I go out again, if all is well then overreaction of the governor theory it is, and I make a mental note to throttle back for 10 minutes before heading towards any pontoons at speed, ideally giving neutral/astern a try in open water before it becomes critical!!!

Thanks for the reassurance hopefully now I find nothing wong when I check it.

Chris
(No??, Habendum of Emsworth)


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