JP3 Thowing Oil out of Exhaust

[steve.sharratt]

At the end of last season we had a quick jaunt to the top of the Lee and Stort rivers.  On parts of the Stort our deep draft really struggled and we were dragging the bottom for long periods.  At the time, I thought this may do the JP3 a favour and provide some load but she started throwing oil out of the exhaust, enough so that we were looking like a couple of coal miners and the roof was covered in oil.  Normally she runs very clean with very little to no smoke.  We have only had this boat for a season and a bit so still getting to know her.  Generally she runs beautifully but does have this occasional cough. (I will try to post a short video. - nope. Doesn’t seem to accept MP4!!) Her last run of the season was a short hundred yard dash but she had this cough continuously which was concerning.  I started her today and everything seems fine.

 

I have alway run on high compression and am now wondering whether I should have switched to low? I am mostly on the Thames so it does get a work out sometimes but, as I say, I always run on high.  Is it possible that I caused oil to be forced out through the exhaust as I was runnning a high load on high compression?  Also, could the ‘cough’ be related to the compression knobs as sounds like a puff of air (e.g. air leak)? 

 

Cheers

 

[Eeyore]

A sticking valve can sound like that.

Oil running down a worn valve guide, but is that a thing with the JP?

[MtB]

3 hours ago, steve.sharratt said:

(I will try to post a short video. - nope. Doesn’t seem to accept MP4!!)

 

Bung it onto youtube, then post a link.

[john.k]

I once put a set of new rings in a JP4.......the chrome bores couldnt be honed ,and so I assumed it would run in .......no way .....clouds of smoke ,and it burnt five gallons of oil in  few hours ......run light it would dribble black oil out the exhaust,full throttle,and it laid a destroyer like smoke screen.

[David Mack]

Any help?

What oil are you using?

[steve.sharratt]

11 hours ago, MtB said:

 

Bung it onto youtube, then post a link.

It sounded easy but this took me 45min!! Hope this works. 

 

 

10 hours ago, David Mack said:

Any help?

What oil are you using?

It is Morris SAE30 (I think). 

Edited February 21, 2023 by steve.sharratt

[BWM]

Have you got the decompression buttons on the side of the engine? If one of those is pushed in it can cause these symptoms. If not i suspect a ring may have broken.

[steamraiser2]

Most likely to be worn valve guides and / or worn rings. The cough sounds like a sticking valve. Heads off I'm afraid

[steve.sharratt]

24 minutes ago, BWM said:

Have you got the decompression buttons on the side of the engine? If one of those is pushed in it can cause these symptoms. If not i suspect a ring may have broken.

I do but I use them at every start so it shouldn’t be that.  I hope it isn’t a broken ring!!

[BWM]

19 minutes ago, steve.sharratt said:

I do but I use them at every start so it shouldn’t be that.  I hope it isn’t a broken ring!!

The picture shows our boat after an 'engineer' fitted chrome rings to chrome liners, which would give a similar result to a broken ring, and was accompanied by similar miss fires. 

[Tracy D'arth]

Is it lube oil or fuel its chucking out?  If its fuel you could have a duff injector.

[john.k]

Chrome rings in chrome bores do make a mess........its also likely something no millenial has ever heard of ........lots of motors used chrome bores once ...Ford ,Leyland,Perkins,Lister ,Ruston,Meadows,Mc Laren ......any others?

[alan_fincher]

45 minutes ago, BWM said:

The picture shows our boat after an 'engineer' fitted chrome rings to chrome liners, which would give a similar result to a broken ring, and was accompanied by similar miss fires. 

 

That's quite impressive!

 

Before being rebuilt, one of our boats (Lister HA2) was spreading a fair amount of oil on the roof. but nothing like that!

[steve.sharratt]

1 hour ago, Tracy D'arth said:

Is it lube oil or fuel its chucking out?  If its fuel you could have a duff injector.

Definitely oil.

[steve.sharratt]

2 hours ago, BWM said:

The picture shows our boat after an 'engineer' fitted chrome rings to chrome liners, which would give a similar result to a broken ring, and was accompanied by similar miss fires. 

Similar but not quite as bad as that.  I got a finer mist, so much so, that we didn’t really notice at first (first sign was that my wife had a few beauty spots I hadn’t noticed before!).  I should add that it did seem to clear itself when back on the Thames.  It took a while so I am not sure if was just residue oil in the manifold or the problem still exists.  E.g how many hours would it take to clear?  When I started it yesterday for the first time this year it wasn’t smoky at all.

[Tracy D'arth]

9 minutes ago, steve.sharratt said:

Similar but not quite as bad as that.  I got a finer mist, so much so, that we didn’t really notice at first (first sign was that my wife had a few beauty spots I hadn’t noticed before!).  I should add that it did seem to clear itself when back on the Thames.  It took a while so I am not sure if was just residue oil in the manifold or the problem still exists.  E.g how many hours would it take to clear?  When I started it yesterday for the first time this year it wasn’t smoky at all.

Is it still misfiring though?

[steve.sharratt]

7 minutes ago, Tracy D'arth said:

Is it still misfiring though?

It didn’t yesterday but it is not consistent and I haven’t been able to pin it down to any specific action/speed/load etc.  Sometimes it will be a single miss (as per the video), other times it can be several in a row and other days, not at all. The reason I mentioned the hi/lo compression dials in the op is that I wondered whether one of them is not sealing. Properly.  Only one of the three moves freely so I assume the other two are coked up.

[Eeyore]

Do you do your on maintenance? Could you take the rocker covers off and perform a "waggle" check on the rocker to rocker shaft clearance and the valve to valve guide clearance? I'm sure a JP owner could talk you through the process.

It about "non intrusive" checking that can be done to give a rough idea of the state of the top end. Basically its the same as checking the tappets.

 

 

Edited February 21, 2023 by Eeyore

[David Mack]

24 minutes ago, steve.sharratt said:

It didn’t yesterday but it is not consistent and I haven’t been able to pin it down to any specific action/speed/load etc.  Sometimes it will be a single miss (as per the video), other times it can be several in a row and other days, not at all.

That would be consistent with a sticking valve, as suggested by @steamraiser2 above.

[Eeyore]

8 minutes ago, David Mack said:

That would be consistent with a sticking valve, as suggested by @steamraiser2 above.

So the exhaust valve and spring may well be covered in soot if the guides and valves are that badly worn. Used to see this a lot on the smaller English Electric diesels, although on those you could change the exhaust valve with the head in situ.

[john.k]

Its a bit hard to tell from the utube ,as its short.

[BWM]

2 hours ago, alan_fincher said:

 

That's quite impressive!

 

Before being rebuilt, one of our boats (Lister HA2) was spreading a fair amount of oil on the roof. but nothing like that!

This was fresh out of a rebuild, and the deposit shown was created in 60 - 90 minutes running! 

[alan_fincher]

18 minutes ago, BWM said:

This was fresh out of a rebuild, and the deposit shown was created in 60 - 90 minutes running! 

The rebuilder didn't happen to have the initials JR, by any chance?

[steamraiser2]

Several suggestions as to the probable causes, or causes, of your problem. If I  were you I  would try the simplest option first and get the injectors pop tested. It only takes a microscopic amount of water to trash an injector. 

If they prove to be OK everything else will need the heads taken off. Not difficult to do but starting at the easiest/cheapest option makes good sense.

 

[steve.sharratt]

3 hours ago, Eeyore said:

Do you do your on maintenance? Could you take the rocker covers off and perform a "waggle" check on the rocker to rocker shaft clearance and the valve to valve guide clearance? I'm sure a JP owner could talk you through the process.

It about "non intrusive" checking that can be done to give a rough idea of the state of the top end. Basically its the same as checking the tappets.

 

 

Good idea.  The rockers are off before every start.  I will have a look asap.  The previous owner said that he had the engine pulled down before he installed it and the engineer said it looked like it had been rebuilt and not run as it was in perfect condition (I have no reason to doubt him).  I have done about 300 hours and the previous owner had likely done less than 50.  Agree that I tackle the least intrusive options first.  The inconsistency of the problem is interesting though. 

22 minutes ago, steamraiser2 said:

Several suggestions as to the probable causes, or causes, of your problem. If I  were you I  would try the simplest option first and get the injectors pop tested. It only takes a microscopic amount of water to trash an injector. 

If they prove to be OK everything else will need the heads taken off. Not difficult to do but starting at the easiest/cheapest option makes good sense.

 

Agreed.  I plan to start at the easy point and work forward from there.  I will keep you posted