Beta 25hp, wont pass 1,000 revs until throttle back & forward again

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aidancoughlan

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I've a newly installed 25hp Beta (last year), and noticed this season that <u>when I leave the berth she wont pass 1,000 revs even at full throttle. When I throttle back and forward she still wont go past 1,000 revs, but when I throttle back to neutral and then full forward she is fine. </u>This behaviour has repeated itself consistently at least the last 5 or six times out this season. Once she gets "unstuck" she is fine, powers the boat along at around 6 knots easily (though only reaches 3,000 revs, not 3,600 max revs - the prop may be slightly over-pitched).

Any ideas why this might be ? Supplier had a look today & was puzzled - has never seen this before (it behaved as described on queue). He looked at the engine while I was demonstrating this & the morse lever etc is all working ok - he then reckoned that maybe the "rack" might be sticking (although he hasnt seen this in a new engine before). He reckoned I am a bit easy on the engine (which is probably true), and recommended working it a bit harder, accelerating faster on the assumption that this may loosen it up.

The only other symptom I can describe is that when we drive away from the berth we have been noticing quite a bit of vibration on the tiller. I think this might be our Kiwi prop sticking after the initial reverse out - it hasn't been greased yet after it's first year, had a reasonable amount of fouling when we lifted out, and the blades (especially one) is stiff to turn full movement (though still no problem to turn by hand). When I throttle back to "unstick" the 1,000 revs limit, after accelerating again the vibration is gone. Could these be related ? If the Kiwi blade somehow stuck at 90% to the water, could the pressure be so much that it loads the engine enough to stop it passing 1,000 revs ?

(BTW we've noticed bad reverse performance lately, and on lift-out today we find that the "reverse rollers" have fallen off the Kiwi prop after one season, not impresed ! However, caught Andy in the Vectra Marine office on Saturday his day off, and he rushed to the post office to send replacements hopefully for Monday, so can't complain. He reckoned they had another customer who had this problem as a result of a rope wrap, though I don't think we've had one . I just mention this in case anybody knows this prop and might connect it with the engine performance.

Any thoughts appreciated...
 
Re: Beta 25hp, wont pass 1,000 revs until throttle back & forward agai

If the prop is stuck at 90º then you should experience black smoke when accelerating.Another thing to check is how the cable is actuating the throttle arm on the injection pump.Also the governor could be sticking.The throttle actuates the governor wich in turn controls fuel delivery.If the weights are stuck then the engine won't get enough fuel .Throttling back and forth may unstick them.
 
Definitely sounds like the prop. Similar behaviour (misbehaviour?) has been reported on here several times. The prop needs greasing as there is no mecahnical means of moving the blades. If you still have the fixed prop try that to eliminate the problem and determine that there is nothing wrong with the engine.
 
Re: Beta 25hp, wont pass 1,000 revs until throttle back & forward agai

30Boat, Tranona, Thanks for suggestions...

The prop is sounding less likely to me since no black smoke- assuming it would produce black smoke within 10 minutes (We left it around this long at 1,000 revs max before clearing it by returning to neutral).

The supplier (Irish beta distributor) check it out today, and had a good look at the engine while I was trying various throttle changes, reckoned all was fine based on visual observation in the engine bay, so I guess he has checked the throttle arm etc, though I will quiz a little more when we talk next.

I don't yet know exactly how the governer works, but it sounds like something internal to control fuel - sounds a likely culprit to me, gives me some reading/self education to do!


Don't have the original prop any more, but the suggestion to rule out the prop makes me wonder if I should try to see if this behaviour persists from cold in neutral without leaving the marina berth - ie. will it exceed 1,000 revs in neutral. Will check once back in the water. If this problem shows up then, it will rule out the prop.
 
Re: Beta 25hp, wont pass 1,000 revs until throttle back & forward agai

I'd lay a £ : 1p that it's the prop, having had very similar problems from my Autoprop once when it got badly fouled.

Try a couple of open throttle runs, still tied up, in reverse and forward gears to free it up.
 
Re: Beta 25hp, wont pass 1,000 revs until throttle back & forward agai

Try a simple test

IF the engine wont rev when there is no gear selectedi.e. in neutral then it must be the injection pump.

If it wont rev when its in gear it could be the gear box, gear lever setting, the prop OR it could still be the injection pump.

By injection pump I mean the cold start (if there is one), the rack, and or the govenor.

I should take a good engine Man about thirty seconds to determine the what is at fault at this level.

Finding the actual bit thats faulty could be a liftout if we determine the prop is the culprit or a strip down of the injection pump.

If the guy is puzzled - find another guy!
 
Re: Beta 25hp, wont pass 1,000 revs until throttle back & forward agai

[ QUOTE ]
I'd lay a £ : 1p that it's the prop, having had very similar problems from my Autoprop once when it got badly fouled.

[/ QUOTE ]
I do still suspect the possibility that the prop might be involved in some way (simply because the tiller vibration ceases at the same time as power is restored when I throttle back to neutral and then drive forward again - hard to put this down to coincidence every time). Having lifted out yesterday though, I can confirm that the prop was not fouled by rope/net etc. However, the Zytel blades were fouling somewhat on the Boss - which according to the manual is imperative to avoid in order for the blades to feather easily. They are still easy to move past the resistance by hand though, so the jury is still out.
I will get the prop dismantled/cleaned before lifting back in next week, so if the problem goes away then it will answer this theory.
 
Re: Beta 25hp, wont pass 1,000 revs until throttle back & forward agai

[ QUOTE ]
IF the engine wont rev when there is no gear selectedi.e. in neutral then it must be the injection pump. ......By injection pump I mean the cold start (if there is one), the rack, and or the govenor.

[/ QUOTE ]
If the problem persists after going back in (ie. cleaning the prop doesnt fix it), this is top off my list to check.

The guy who looked at it for me is the Beta distributor in Ireland who came highly recommended by Beta UK, I hope he knows what he is doing. He travelled about 2.5 hours to come look at it. If it persists though I might get another local Dublin engineer to give a second opinion. Since it rectifies itself quickly (on throttling back to neutral & acccelerating again), I don't mind the "inconvenience" for local day/weekend sails but would like to know what the problem is before going cruising for a few weeks in August in case it develops into something more serious.
 
Re: Beta 25hp, wont pass 1,000 revs until throttle back & forward agai

You can check the out of gear (and in gear) throttle settings whilst ashore. Just remove the impellor and run the engine. You should be able to run for 5 minutes without getting the engine too hot. This should rule in/out the prop.
 
Re: Beta 25hp, wont pass 1,000 revs until throttle back & forward agai

There could be more than just one problem.

Sometimes my engine would start and run with no problem. Sometimes it would start but not take a load and would only rev to little more than 1,000 rpm.

It transpired that I had a part blocked fuel filter. Water in the fuel collected in the filter unit until the paper (or whatever it was made from) filtering parts decomposed and restricted fuel flow.

To compound the issue, weed had collected round the prop and was invisible from deck.

Confused, well, I was until the penny dropped and we realised there were more things going on, all at once too ! !
 
Re: Beta 25hp, 1,000 revs max - Photos of Kiwi Prop blades

Thanks all for responses. After examining it more closely today, I am strongly suspecting the prop at this stage.

The KIWI Prop has "reverse rollers" on the Boss which stop the feathering blades from rotating too far when in reverse. (I dont understand why it isn't a simple stopper, if anyone knows pls do tell). As mentioned in my earlier posts, 2 of the three reverse rollers have fallen out. Looking at it closer today, this has a significant effect on the angle of the blade if it were in reverse position when I start to move forward.

Here is a photo of the blade in normal "forward" position.
KIWIProppitchforwardwhenbladerev-1.jpg


Here is a photo of the blade in "accidental forward" position, where it might be when I move into forward after being in reverse.

This position of a fairly extreme pitch is only enabled because the rollers are missing. I presume this angle is a fairly extreme pitch & could overload the engine ? I dont know why it never created black smoke though as suggested earlier. Maybe this would take time - I have been "unsticking" it by going to neutral & back after the first couple of minutes out of the berth.
KIWIProppitchforwardwhenbladerevers.jpg


The "Reversing roller" is the thing with the Allen key head on the bottom left side of the Boss in this picture... you can see the spot on the top where one of the 2 others is missing.
KIWIPropmissingreverserollers.jpg


Here you can see the one remaining reversing roller hanging out, which is worrying since KIWI's manual suggest that they can only be removed with heat.
KIWIPropreversingrollerloosecloseup.jpg


Is the angle of pitch in the second photo above likely to be the cause of the 1,000 revs maximum?. It could also explain the vibration on the tiller, and the fact that this vibration disapears at the same time that the maximum revs limit disapears - when I move into neutral. While I am gliding along in neutral, presumably the blades feather to the water flow, and pick up the correct angle when moved into forward ?
 
Re: Beta 25hp, 1,000 revs max - Photos of Kiwi Prop blades

Yes, I think that is your answer. Prop needs fixing.

BTW you are very short of clearance between the front of the rope cutter and the P bracket. There should be 15-20mm and guess you only have about 5. This is not enough for the water flow through the cutless and you run the risk of the cutter hitting the P bracket when the engine moves forward as you engage gear. This will lead to short bearing life of the cutter. Go onto www.ropestripper.com to get the correct dimensions. You will almost certainly need a 15mm spacer on the back of the gearbox to move the shaft back. You will also need to reposition the striker plate on the P bracket to locate the fixed cutter properly. Once again all the dimensions on the site.
 
Re: Beta 25hp, 1,000 revs max - Photos of Kiwi Prop blades

Thanks Tranona. Stripper was just fitted yesterday by same engineer that fitted the prop & engine last year. The Ambassador instructions at http://www.ropestripper.com/documents/fitting-am5-10-15.pdf dont actually say anything about the clearance behind the P-bracket, but it does stand to reason, and I think I remember reading this somewhere when reading about rope strippers. I will bring this up with the engineer that fitted it.

Email, photos & video sent to Kiwi re: the prop.
 
Re: Beta 25hp, 1,000 revs max - Photos of Kiwi Prop blades

Yes, if you look at the instructions you will see that the gap between the front of the prop and the P bracket needs to be 40mm. Cutter is 30mm so leaving a minimum of 10mm. It is unusual for this gap to be there on existing installations - normal is 20mm, so a spacer needs to be fitted. Your original gap is a bit bigger than that - but not enough! There is no problem with the gap being bigger as the extra space is left between the prop and the cutter. Have a look on the accessories page on the site for spacers which are available in 5mm increments from 10mm up. Do the measurement of the gap first to find out how thick a spacer you need. The striker will need to be positioned further back on the P bracket so will need re-drilling and fixing on the other side.
 
Re: Beta 25hp, 1,000 revs max - Photos of Kiwi Prop blades

Hi Aidan

Have sent you a PM - look for the flashing message on the header - with some important information about your stripper.

Regards
 
Re: Beta 25hp, 1,000 revs max - Photos of Kiwi Prop blades

Thanks Tranona for the info and PM. The gap for my AM5 size is only 36mm as you mentioned in the PM. I remember him measuring 36mm (while I was there doing other jobs, and I pointed out that the instructions say that there is no maximum, but he wanted to keep the prop as close to the P-bracket as possible).

I do believe the cutter looks quite close to the P-bracket for comfort though, acknowledged by Ambassador by email this morning: "... Your installation stands a good chance of the Stripper rubbing against the P bracket and restricting the water flow through the bearing. You could extend the propeller shaft with our Spacemaker Shaft spacers or by drawing the shaft out of the Half Coupling, either way the Striker Plate will need to be repositioned further aft...."

Incidentally, Alan from Kiwi rang me first thing this morning after an email last night - they are quite surprised by the scenario with the prop (the manual insists that it is impossible to remove the reversing rollers without heat!). He's asked for the entire assembly back to examine it & will turn around in 24 hours. That's great service, they seem quite helpfull. I will post again when we get to the bottom of it.
 
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