DM2 tickover

[Richardcn]

Hi all

 

So first 'problem'. Ran the RN this evening and found the tickover high, as picked up on the survey. On advice from another DM owner adjusted it down and all seemed fine. However, whilst getting on with other things found the rpm would increase again randomly. Pushing the lever as if to stop the engine brought it back again but same thing happened several times. Any ideas? Setting off tomorrow morning so will see if it affects cruising and report back.

Thanks

Richard

[Mike Tee]

When you say it increased, by how much?

They do tend to fluctuate a little (well mine does anyway) but only by about 40-50rpm while ticking over out of gear.

Give it a good run tomorrow and listen while in gear under load and you may find you are worrying about nothing.

Do bear in mind I'm not an expert on RN internals, not even an amateur mechanic!!!

[Timleech]

Hi all

 

So first 'problem'. Ran the RN this evening and found the tickover high, as picked up on the survey. On advice from another DM owner adjusted it down and all seemed fine. However, whilst getting on with other things found the rpm would increase again randomly. Pushing the lever as if to stop the engine brought it back again but same thing happened several times. Any ideas? Setting off tomorrow morning so will see if it affects cruising and report back.

Thanks

Richard

 

Does it change if you rock the boat?

[frangar]

Also bear in mind any electrical load cutting in and out....it's quite a high geared alternator.

 

My JP does vary as well...it's actually more noticeable when the engine is very lightly loaded....eg in neutral with little loading from the alternator,......you learn to live with it!

 

Cheers

 

Gareth

[MtB]

I suggest you get a nice three cylinder Kubota.

 

I'll take that useless RN off yer hands for £50 to help you out.

 

 

MtB

[Richardcn]

 

When you say it increased, by how much?

They do tend to fluctuate a little (well mine does anyway) but only by about 40-50rpm while ticking over out of gear.

 

Give it a good run tomorrow and listen while in gear under load and you may find you are worrying about nothing.

Do bear in mind I'm not an expert on RN internals, not even an amateur mechanic!!!

The change is quite significant. I'm not familiar enough with the engine yet to be able to say how much but it did have me concerned that it was about to run away occasionally, it never did of course! I will see how it goes tomorrow, maybe it's nothing, just normal behaviour.

Richard

 

Does it change if you rock the boat?

I didn't try but can do tomorrow. It could have been as I was moving around the boat. Why?

Also bear in mind any electrical load cutting in and out....it's quite a high geared alternator.

 

My JP does vary as well...it's actually more noticeable when the engine is very lightly loaded....eg in neutral with little loading from the alternator,......you learn to live with it!

 

Cheers

 

Gareth

Yeah sounds very similar but as it is such a low rpm engine it was a bit worrying. Will see how it goes over the following days.

Richard

Edited May 25, 2015 by Richardcn

[Mike Tee]

You say the change is quite significant - I'd not class that as normal. If it were mine, I'd see how it performs in normal cruising conditions, but if it continued to increase revs on tickover then would for sure have it looked at.

Buy some lemons for tomoro just to wipe the silly grin off after cruising.

Edited May 25, 2015 by Mike Tee

[Richardcn]

I suggest you get a nice three cylinder Kubota.

 

I'll take that useless RN off yer hands for £50 to help you out.

 

 

MtB

It never ceases to amaze me just how far people will go on this forum to help out. That's a done deal Mike. But can you just confirm, what is a Kubota?

Richard

You say the change is quite significant - I'd not class that as normal. If it were mine, I'd see how it performs in normal cruising conditions, but if it continued to increase revs on tickover then would for sure have it looked at.

Buy some lemons for tomoro just to wipe the silly grin off after cruising.

Too late, the shops are shut! Guess I'll have to grin and bear it then ;j

Richard

[Dave Clinton]

Hi all

 

So first 'problem'. Ran the RN this evening and found the tickover high, as picked up on the survey. On advice from another DM owner adjusted it down and all seemed fine. However, whilst getting on with other things found the rpm would increase again randomly. Pushing the lever as if to stop the engine brought it back again but same thing happened several times. Any ideas? Setting off tomorrow morning so will see if it affects cruising and report back.

Thanks

Richard

sticky governor arm ( the one that goes through the injector pump)? try a spot of oil on each end.

[by'eck]

sticky governor arm ( the one that goes through the injector pump)? try a spot of oil on each end.

 

That's the first thing I would try. Check the injection pump rack arm and its linkages for free movement and play. At idle with no load a tiny movement will make a big difference to revs.

[Timleech]

Does it change if you rock the boat?

 

 

I didn't try but can do tomorrow. It could have been as I was moving around the boat. Why?

 

 

Richard

Certainly on Nationals any list on the boat can have a small effect on tickover speed, because the weight of various components is either being pushed uphill or downhill according to the angle. Mind you, the National governor design is crap, especially when it has 50 to 80 years' wear built in. The original RN governor is a bit better, but I can still imagine that sort of effect arising. I think they did imrove the governor design for later engines, but can't remember the details.

 

Tim

[by'eck]

 

 

Certainly on Nationals any list on the boat can have a small effect on tickover speed, because the weight of various components is either being pushed uphill or downhill according to the angle. Mind you, the National governor design is crap, especially when it has 50 to 80 years' wear built in. The original RN governor is a bit better, but I can still imagine that sort of effect arising. I think they did imrove the governor design for later engines, but can't remember the details.

 

Tim

 

Interesting point. When I snag my boat whilst tying up with centre line, and it heels a little, I can often hear idling revs drop a little before picking up. Guess that's only going to happen on vintage engines with high rotating mass.

[Timleech]

 

Interesting point. When I snag my boat whilst tying up with centre line, and it heels a little, I can often hear idling revs drop a little before picking up. Guess that's only going to happen on vintage engines with high rotating mass.

 

More to do with having a transversely mounted inline fuel pump, methinks.

[Richardcn]

sticky governor arm ( the one that goes through the injector pump)? try a spot of oil on each end.

Sorry for the late reply, long cruising day today and then locked myself out of my account and rubbish signal here. I think that sounds like it might have been the problem but also the tickover was way too high. I got fed up with that after a couple of hours, sitting in locks chugging away so fiddled with what I presume to be the adjuster. Went too far and had a couple of stalls leaving locks so tweaked again and for the 2nd half of the day she was purring . A gentle putt putt out of gear and no stalls putting in gear and tickover in and out of gear seems good. I think it self lubricated after a long day cruising. Many thanks for all the advice. I'll probably be back with something else tomorrow

Richard

[Athy]

. I think it self lubricated after a long day cruising.

Many of us do that. Ruddles or Directors' are my self-lubricating favourites.

 

But seriously, I am pleased to read that the problem seems to be sorting itself out.

[MtB]

Many of us do that. Ruddles or Directors' are my self-lubricating favourites.

 

 

 

You're kidding!? Where can you buy well cellared Directors' nowadays?

 

I hardly ever see it, and when I did last year, it was grim.

 

 

MtB

[Athy]

 

 

You're kidding!? Where can you buy well cellared Directors' nowadays?

 

I hardly ever see it, and when I did last year, it was grim.

 

 

MtB

In tins from the supermarket. The four which I downed yesterday evening were far from grim.

[MtB]

In tins from the supermarket. The four which I downed yesterday evening were far from grim.

 

Tinned beer is usually stupidly fizzy...

 

Anyway if it's that good why don't they sell it in pubs in tins instead of from barrels?!

 

 

Mtb

P.S. Even so, I'll get some in and seef I agree with you!

[Athy]

 

Tinned beer is usually stupidly fizzy...

 

Anyway if it's that good why don't they sell it in pubs in tins instead of from barrels?!

 

 

Mtb

P.S. Even so, I'll get some in and seef I agree with you!

The value of research cannot be overstated.

Yes, best to open the can a couple of minutes before pouring the ale.

[Mike Tee]

Sorry for the late reply, long cruising day today and then locked myself out of my account and rubbish signal here. I think that sounds like it might have been the problem but also the tickover was way too high. I got fed up with that after a couple of hours, sitting in locks chugging away so fiddled with what I presume to be the adjuster. Went too far and had a couple of stalls leaving locks so tweaked again and for the 2nd half of the day she was purring . A gentle putt putt out of gear and no stalls putting in gear and tickover in and out of gear seems good. I think it self lubricated after a long day cruising. Many thanks for all the advice. I'll probably be back with something else tomorrow

Richard

The DM2 takes quite a while to get fully warmed up, so now you have set it to tickover comfortably, you did that while it was warm. Don't be surprised if it tries to stall after you first fire it up, just wind it up a bit, it will eventually settle.

[captain birdseye]

Did you oil the governor. There is an oil point on the top of it. It may have been sticking if not oiled and left standing for a while. These tend to self lubricate when the engine is hot, but if in doubt give it a quick spurt of oil.

After the BCN Challenge and a quick four day run back up to the Peak Forest I have developed, a small leak from the water pump drive shaft, the first problem the RN has given me. Decided as the shaft appears to be worn I would bite the bullet and order a replacement pump.

Edited May 30, 2015 by captain birdseye