RN slowly died

[Tuscan]

Towards the end of last year, I had an intermittent problem where we lost power and we're stuck on tick over then a clunk the engine would free itself , with a belch of black smoke, and then be fine.

 

This year we haven't been to the boat since January as I had a serious op, but I did arrange for injectors to be sent away and serviced. This weekend managed to come up and engine started in marina, next morning feeling ok I motored the mile down to Foxton and we spent the night all good, Friday we motored down into basin for water and services, spun and moored again all fine.

 

Today I started engine to return and after 100M we were stuck on tick over with no throttle response, again clunk belch of black smoke and some high revs which took a while to settle down then engine stalled. After several attempts restarted but again no throttle response but this time in quite high revs stayed like this for best part of a mile back to the marina , managed to moor up with some difficulty.

 

Plenty of oil and no obvious oil leaks, engine now will not start.

 

I fear the worse - any thoughts?

[MtB]

Sounds like a governor problem to me. Medium/expensive if I'm right.

 

Have you tried cracking the injector pipe unions to see if fuel is arriving at both cylinders?

High revs then stalling and refusing to start sounds like air in the fuel. Possibly a failure unrelated to the clunk.

[Tuscan]

I'm a numpty - engineer here at Debdale just gone on holiday. be keen for any recommendations of an engineer with knowledge of RNs to have a look.

[MtB]

I've seen Jonno at Union canal Carriers Braunston highly recommended on here.

 

Or RLWP but he's a bit tied up this weekend exhibiting at the Braunston historic boat rally.

Or try this bunch!

 

http://www.rnregister.org.uk/

[Tuscan]

Thanks - was going to give the guys at Hillmorton a call as they own RN. Thought RLWP was a lister specialist if not good call.

[Tony Dunkley]

Towards the end of last year, I had an intermittent problem where we lost power and we're stuck on tick over then a clunk the engine would free itself , with a belch of black smoke, and then be fine.

 

This year we haven't been to the boat since January as I had a serious op, but I did arrange for injectors to be sent away and serviced. This weekend managed to come up and engine started in marina, next morning feeling ok I motored the mile down to Foxton and we spent the night all good, Friday we motored down into basin for water and services, spun and moored again all fine.

 

Today I started engine to return and after 100M we were stuck on tick over with no throttle response, again clunk belch of black smoke and some high revs which took a while to settle down then engine stalled. After several attempts restarted but again no throttle response but this time in quite high revs stayed like this for best part of a mile back to the marina , managed to moor up with some difficulty.

 

Plenty of oil and no obvious oil leaks, engine now will not start.

 

I fear the worse - any thoughts?

 

As this is a return/recurrence of the same fault you had last year, and it now can't be the injectors, it is almost certainly a sticking valve, or valves.

 

You will probably be able to a temporary 'fix' yourself, but the reason for the sticking valve(s) will need attention, . . . . otherwise it will just keep happening repeatedly.

 

I've sent you a PM with my phone number. If you're at Foxton, then I would be able to get out to you tomorrow.

[Tuscan]

Thanks Tony - will call in the morning.

[matty40s]

another one to try is Richard Milligan (Marine Engineering Co) on 07973 826260. He has rebuilt/repaired a couple of RN's on Stowe Hill boats that I know of.

Sounds like a fuel pump or governor issue to me too(from experience)

[Tuscan]

Tony Dunkley kindly talked me through basic fault finding , it would appear we have two sticky valves at the exhaust side probably caused by rain/damp whilst I've been recouperating from my operation. He's offered to come over and check/investigate further - gratefully received.

[BEngo]

Well, if it is sticking valves,the good thing about an RN is that you can get the valves out without taking the heads off. Bit of a faff, couple of special tools make the job easier ( I believe the 'factory' may lend these), but certainly do-able.

 

N

[mross]

I'd be very tempted to disconnect the governor from the fuel rack and see if the rack is free. Then try starting the engine while gradually moving the fuel rack forward. You won't have good control of engine speed but if engine speeds up pull rack towards you. If fuel rack won't move there's the problem. Red arrow shows direction to move rack for more fuel = more revs.

 

 

 

Edited June 26, 2016 by mross

[Tuscan]

I'd be very tempted to disconnect the governor from the fuel rack and see if the rack is free. Then try starting the engine while gradually moving the fuel rack forward. You won't have good control of engine speed but if engine speeds up pull rack towards you. If fuel rack won't move there's the problem.

Thank you the plan is to free valves and then test as you suggest,

[bizzard]

Not conversant with these engines, but for sticky valves is it not possible to pour ReDeX UCL down the induction air intake and with the decompressor levers on give the engine a good whirling over on the starter. If you can get to the valve tappets, rockers or whatever and tap them with a mallet at the same time. Free'd off many valves like that, petrol and diesel. Petrol engines I dribble Redex into the air intake whilst the engine is running, but DON'T to that with a diesel.

Edited June 26, 2016 by bizzard

[mattlad]

Silly question alert. Have you changed the fuel filter?

 

I think that Tony's diagnosis sounds like a good call, we had a stuck valve on our RN and when it releases it goes with quite a bang!

 

I'll second Richard Milligan to take a look for you, he knows his way around RNs and he is also a member of the Register.