Runaway Engine Woes

[Ocean30]

Hi all

 

Im new to this forum and find myself here for what was a very worrying event today. I have an old Ocean 30 with a 1.8 bmc engine.  I’d noticed over time that the oil level had risen and the oil felt a bit thin. I was going to change the oil in the next couple of weeks but felt that going out for an hour today would be fine…..how wrong could I be😩. 
The warning signs were already showing some engine hours ago. Oil pressure dropping off after being run for 30 minutes or so. Just put it down to worn oil. So…….out today and helped a fellow boater out as they’d broken down. Towing him back and then the engine made a loud tapping. Immediately off the throttle but the engine continued to build revs. I knew what was happening but basically cleared the area as I was worried about the engine exploding. It ran up for around 1 minute before it died down. I’d shut all fuel off to the engine. 
I’d been filling up with the new bio fuel locally that I have since learnt now kills the diesel pump seals and dumps diesel into the sump eventually causing runaway. I should’ve have anticipated this having made bio diesel for my cars in the past and dealing with failing diesel seals. Rubber becomes very elastic. 
 

So Im thinking I need my pump seals done. Is this an easy job? Does anyone know an exchange service? Also how knackered could my engine be? What’s the best things to check for. Or is it a case of replace oil and pump then hope for the best? I’ll turn the engine over manually, I suppose I can check cylinder pressure? I know a bit about engines and these don’t seem over complicated. 
 

I’d really appreciate some advice. 
 

Many thanks 

 

Simon 

[booke23]

Many years ago I had a Perkins engine runaway on a tractor. I stopped the tractor in the yard and closed the throttle. The engine just revved uncontrollably...the rev counter went way past the red line of 2250rpm. The stop lever had no effect and due to the confined space it was in and ropey clutch I couldn't risk trying to stall it. It was a disturbing experience to say the least.

 

I pulled the low pressure diesel supply pipe from the injector pump and after what seemed like an age (probably a minute) it ran out of diesel and stopped. I was convinced the engine would be scrap however I got a diesel injection specialist to look at the injector pump and it turned out a failed rack mechanism was the cause. He fixed it and the engine started up and operated normally for many years after that event! Since then I always try to have a plan in the back of my mind to stop a runaway diesel.......a CO2 fire extinguisher into the air intake should do it.

 

If you change the oil and check the levels regularly to make sure it doesn't overfill, you could probably use the engine normally until you get it fixed. As a general rule diesel fuel injection pump repair is best left to a specialist. 

[Tracy D'arth]

Depends on what the loud tapping noise was due to. At worst it could have broken the crank.  Whatever it was, it sound terminal.  Its worrying that it stopped itself, shutting the fuel off will not usually stop a run away as it is burning the oil out of the sump.

I would spend no money on the pump until you know that the engine is OK mechanically. 

 

Get a CO2 extinguisher ready next to the air intake and start it again. If it wont start I would assume it is busted.

[Tony Brooks]

Yes, replace the oil and give it a good test as Tracy suggest only if it all sounds OK would I get the pump fixed. Also make sure the lift pump diaphragm is not leaking because that can leak into the sump.

 

I don't think this problem is as much to do with biofuel as it is to do with the effect of the old high sulphur diesel on the seals and the lack of sulphur in modern diesel of any sort.  The old sulphur in the old diesel entered the seal material and caused it to swell so as the seal wore the swelling took the wear up. with low sulphur diesel the sulphur in the seal leaches out over time so the seal returns to its original worn size so as it leaks. At one time if you took the top off the lift pump and  pulled the seal out you would often not be able to put it back because of the swelling. This is far less common nowadays.

[Ocean30]

Ok thanks for the replies I’ll turn it over with a spanner tomorrow and see how it feels. 
Assuming if I do get it started it would only runaway again when hot not cold? 
she’s a lovely old boat and would be devestated if the engine was cooked. Also out of pocket…..😩

[Tony Brooks]

1 minute ago, Ocean30 said:

Ok thanks for the replies I’ll turn it over with a spanner tomorrow and see how it feels. 
Assuming if I do get it started it would only runaway again when hot not cold? 
she’s a lovely old boat and would be devestated if the engine was cooked. Also out of pocket…..😩

 

WE can't guarantee it wont run away but with the correct amount and grade of oil in the sump it is unlikely.

[Tracy D'arth]

6 minutes ago, Ocean30 said:

Ok thanks for the replies I’ll turn it over with a spanner tomorrow and see how it feels. 
Assuming if I do get it started it would only runaway again when hot not cold? 
she’s a lovely old boat and would be devestated if the engine was cooked. Also out of pocket…..😩

That is what the CO2 extinguisher is for, spayed into the air intake it will stop a runaway. 

So will blocking the air inlet but do NOT use your hand, it will suck the flesh off.  Use a metal lid, not a rag either.

 

Tony has a good point, check the lift pump diaphragm for the smallest pin hole.

[booke23]

10 minutes ago, Ocean30 said:

Ok thanks for the replies I’ll turn it over with a spanner tomorrow and see how it feels. 
Assuming if I do get it started it would only runaway again when hot not cold? 
she’s a lovely old boat and would be devestated if the engine was cooked. Also out of pocket…..😩

 

If it feels ok when you turn it with a spanner, I wouldn't try starting it until you drain the oil/diesel mix from the sump and fill to the correct level with proper oil as Tony says. Only then would I try starting it, with a plan to stop it if it does runaway again. (CO2 fire extinguisher or proper means to block the intake....block of wood or similar.)

[Bee]

A frightening thing. I've only seen it once and that was from a distance. As Tracey has said a CO2 extinguisher is a Good Idea as is a rag over the air intake. Don't use powder! If the engine is very worn it can use its sump oil and vapour for fuel and that is a problem. Edit. Others don't recommend using a rag in the air intake and they are probably right, a multi cylinder engine going like the clappers might well be pulling in some mighty vacuum

 

Edited December 18, 2021 by Bee

[Tracy D'arth]

1 minute ago, Bee said:

A frightening thing. I've only seen it once and that was from a distance. As Tracey has said a CO2 extinguisher is a Good Idea as is a rag over the air intake. Don't use powder! If the engine is very worn it can use its sump oil and vapour for fuel and that is a problem. 

A rag risks being sucked in and wrecking the engine because it will wedge an inlet valve open, Do NOT use a rag!

[john.k]

Id say it would be a good idea to remove any breather from crankcase/rocker cover to intake pipe......thats been the cause of runaways on BMC motors mentioned previously......and whats caused failure of your pumps seals is 50 years,not some new fuel. ..............i suggest you either geta reco'd pump ,or if the budget doesnt allow that ,then peruse some previous BMC pump reseals ,where alls needed is a pair of bent circlip pliers.

Edited December 19, 2021 by john.k

[cuthound]

13 hours ago, Bee said:

A frightening thing. I've only seen it once and that was from a distance. As Tracey has said a CO2 extinguisher is a Good Idea as is a rag over the air intake. Don't use powder! If the engine is very worn it can use its sump oil and vapour for fuel and that is a problem. Edit. Others don't recommend using a rag in the air intake and they are probably right, a multi cylinder engine going like the clappers might well be pulling in some mighty vacuum

 

 

When i used to project manage the installation of standby diesel generator sets for BT, i used to specify that Chalwyn air shut off valves be fitted to the air inlet to stop the engine in case of overspeed. https://www.chalwyn.com/products/air-intake-shut-down-valves

 

The first time I had one fitted I wanted to see it operate. This was on a Cummins 1000kVA generstor, engine size 50 litres.The engine supply contractor was most reluctant as he was worried in case the sudden stop damaged the crankshaft. It didn't but the engine stopped almost instantaneously.

 

[Ocean30]

Thanks for all your comments. Very helpful. Now going to the dyke to assess the damage. Manually turn engine over, if no nasties change oil. Then probably just check and possibly replace fuel lift pump as I’ve heard that these can also dump fuel into the sump. Cheap to just replace out right. Fingers crossed…….if engine has survived and it turns out to be the pump seals can anyone recommend a good specialist for this repair? Something I could do? Good to hear. 

[noddyboater]

I wouldn't worry too much about mechanical damage. 

I've had the pleasure of working on modern multi valve diesels that have run away at very high speeds- over 6,000rpm,  usually when oil builds up in the intercooler pipes due to a failed turbo. The only parts that need replacement are the injector tips,  presumably because of the excessive heat generated in the cylinders. 

I'd guess the "tapping" noise was hydraulic rather than an actual mechanical failure. 

[Tony Brooks]

58 minutes ago, Ocean30 said:

Thanks for all your comments. Very helpful. Now going to the dyke to assess the damage. Manually turn engine over, if no nasties change oil. Then probably just check and possibly replace fuel lift pump as I’ve heard that these can also dump fuel into the sump. Cheap to just replace out right. Fingers crossed…….if engine has survived and it turns out to be the pump seals can anyone recommend a good specialist for this repair? Something I could do? Good to hear. 

 

when replacing the lift pump it is all too easy to get the operating arm on the wrong side of the camshaft and if you don't realise yu will be buying another pump. You need to slide the operating arm up the inside face of the crankcase and ensure that you can push the pump flange flush with the engine by hand force before bolting up.

[Ocean30]

So I turned engine over manually and all felt fine with good compression no nasty noise. 
changed oil. It was probably an extra 3 litres of diesel that had got in! 
fired her up without issue. No nasty smoke, was at first, but then cleared. Good crank case pressure. Few! Taken off and stripped fuel pump and diaphragm appeared well although it’s hard to no if the rubber has split on the copper plunger that it’s connected to? Ordered a new one. Makes sense!  So I’m guessing if this doesn’t cure it it’s the diesel pump. Any recommendations for services?. I’m assuming they’re relatively easy to remove. I’ll mark up. 
I’ll go for a new seal kit so that it can tolerate the new fuels. I guess its a case of running her for a bit and checking the oil levels prior to anything more drastic.

[Tony Brooks]

Refitting the 1.8 injector pump is probably only beaten to the easiest ever by the 1.5 and that is only to do with slightly easier access. The drive has a master spline so it is impossible to install it in the wrong position.There is an adjustable pointer on the mounting block that stays on the engine that you align with a mark scribed on the corner of the pump flange - that is all there is to it for most people.You are supposed to use a special tool to take the backlash out of the drive and reset the pointer but it will probably be near enough for marine use unless the timing chain is horribly worn.  The pump rebuilder scribes the line.

 

Within the last week or so we had a member who changed his own pump drive seals so look up the BMC 1.5/1.8 pump topics although I would end it away if t were mine.

[Ocean30]

Thanks Tony

To be honest I would do that as it is better to be done properly and guaranteed for piece of mind. 
This forum has been so helpful in this issue so thank you all. I’ll post an update once I’ve fitted the new lift pump. Although I think I already know it’s the fuel injection pump that’s the likely culprit 😬. Not the end of the world and the old girl is worth it. 

[Ocean30]

[Tracy D'arth]

1 hour ago, Tony Brooks said:

Refitting the 1.8 injector pump is probably only beaten to the easiest ever by the 1.5 and that is only to do with slightly easier access. The drive has a master spline so it is impossible to install it in the wrong position.There is an adjustable pointer on the mounting block that stays on the engine that you align with a mark scribed on the corner of the pump flange - that is all there is to it for most people.You are supposed to use a special tool to take the backlash out of the drive and reset the pointer but it will probably be near enough for marine use unless the timing chain is horribly worn.  The pump rebuilder scribes the line.

 

Within the last week or so we had a member who changed his own pump drive seals so look up the BMC 1.5/1.8 pump topics although I would end it away if t were mine.

Tough motors these old BMCs..   Glad its OK.  Runaway thrash has probably decoked it for you.   Don't make a habit of it though!

[Ocean30]

😂. I don’t want to be scared like that again!!!! 

[Ocean30]

I replaced the lift pump and oil. Ran it for a relatively short amount of time before re checking the engine oil. I was quite surprised to see that it had risen quite substantially. I’m guessing diesel pump needs to come off and go away for new seals. I’m assuming these seals will tolerate the fuel I’m using if the low sulphur variant that is being sold locally. Or should I take the old Jerry can down with me to fill up? Using decent diesel from Shell? 

[TNLI]

10 hours ago, Ocean30 said:

I replaced the lift pump and oil. Ran it for a relatively short amount of time before re checking the engine oil. I was quite surprised to see that it had risen quite substantially. I’m guessing diesel pump needs to come off and go away for new seals. I’m assuming these seals will tolerate the fuel I’m using if the low sulphur variant that is being sold locally. Or should I take the old Jerry can down with me to fill up? Using decent diesel from Shell? 

 

When you check the oil oil, (Before every trip), always rub it between your fingers and sniff test when it's warm if the oil might have increased. The human nose can detect diesel fuel when it's more than about 10%. For real long term low block wear 2% is the limit. Using a real good conventional oil, like the Liqui Moly Touring 20w50 does help. Using Shell diesel is slightly better in pump lubricity terms, although you can also use cheap red fuel with a lubricity additive and Bio diesel is good news in lubricity terms, although you can only find a diesel with a good amount of it at farm fuel facilities. Alas it does tend to grow more diesel bug and has a higher flash point, so the diesel that gets past you HP pump seals will not evaporate when the oil gets warm enough, 

 

No idea why you changed the lift pump, as it's nearly always the HP pump seals that fail first, although oddly enough I'm just doing mine, as it's never been changed for at least 50 years. My HP pump was done by the last owner, as were the injectors, but the orrible black paint is all over the lift pump. 

  The lift pump does have a filter screen under the top round bit, but it's rare for that to get dirty. The HP pump, (CAV), also has a filter on the opposite side that is mentioned in the various car manuals.

[Ocean30]

Thank you

 

Although I’m still unsure if new shaft seals are fitted will I face the same problem or are they able to withstand the low sulphur diesel? I don’t want to be refurbishing a diesel pump on an annual basis. I guess the diaphragm could have split on the lift pump and it’s the easiest cheapest place to start. Rule out the easy bits before tackling the more expensive ones 😫. I’m hoping the pump isn’t too fiddly to remove although I note that the nut between the pump and block may be some fun and games! 

[Tony Brooks]

11 hours ago, Ocean30 said:

I replaced the lift pump and oil. Ran it for a relatively short amount of time before re checking the engine oil. I was quite surprised to see that it had risen quite substantially. I’m guessing diesel pump needs to come off and go away for new seals. I’m assuming these seals will tolerate the fuel I’m using if the low sulphur variant that is being sold locally. Or should I take the old Jerry can down with me to fill up? Using decent diesel from Shell? 

 

Before taking the advice about lift pumps not being the likely reason for the oil take a look back at that articular poster's input and decide how informed it may be. I think that you did right, the lift pump can fill the sump with diesel because not all have the drain hole in the base part of the body. A competent pump specialist should fit seals compatible with FAME but with low sulphur fuel they will swell less than with old diesel so will not hide their wear to the same degree.

3 minutes ago, Ocean30 said:

Thank you

 

Although I’m still unsure if new shaft seals are fitted will I face the same problem or are they able to withstand the low sulphur diesel? I don’t want to be refurbishing a diesel pump on an annual basis. I guess the diaphragm could have split on the lift pump and it’s the easiest cheapest place to start. Rule out the easy bits before tackling the more expensive ones 😫. I’m hoping the pump isn’t too fiddly to remove although I note that the nut between the pump and block may be some fun and games! 

 

I think you need 3/8 drive socket on a long "wobble bar" and ratchet for that nut.

Edited January 5, 2022 by Tony Brooks