Help required with a stalling engine.

[jaysparticus]

Hi Folks. Hope your all enjoying the summer!

I have a new dilemma.

I have been out on the boat today - Seamaster 23 with a 1600cc inboard petrol engine - and after 30- 40 min the engine started spluttering and then stalled. i scratched my head for a while and changed the fule filter etc and checked the carb but everything seemed fine but i couldn't get it to start again.
After approx 45 mins i tried again and the engine started and sounded great again so i continued on my journey thinking that i had rectified the problem !

Again after 30 - 40 mins the engine did the same , started spluttering and stalled. I checked the temperature and it was 68deg on the engine and the oil pressure was 28 psi but the engine felt hot to touch... expected.
i removed the carb again and worked the accelerator and i could see fuel injection and atomising due to the heat.

I then thought i may have a blocked vent on my petrol tank and i removed the fill cap and went for a start and woosh it fired up! I believed i had cracked the problem. I had at this time altered the mixture screw etc in my efforts so the engine was running a bit rich .

The boat is putting plenty of water out the back too .

Off i went again on my travels and AGAIN... after 30 - 40 mins the engine stalled again after spluttering and i have the fill cap still off!! each time it takes 45 - 1 hour to restart as if it is cooling down or if the engine is flooded but i have used a colour tuner on the plugs and got it set up perfect.

The engine in essence is brand new and has recently been installed and did run ok but now it is a disaster as on the York river Ouse, the traffic is a lot for a broken down boat to take on!!

Any help and advice will be really appreciated

** if anyone know a good mechanic in york please let me know **

James

 

[Poecheng]

Not sure for a second it is the answer but I used to have a similar problem on a motorbike when (much) younger.

There was too much carbon on the exhaust valve and/or it wasn't seating correctly and when the engine got hot, the slack on the tappets had been entirely taken up and then some so that it slightly opened the exhaust value thus losing compression. Stopped, scratched head, tried everything and by that time the exhaust valve had cooled down and would provide compression again. Off we go again.........

Head off, re-ground the exhaust valve and never did it again.

So, when you splutter to a halt, is there much compression?

 

[kashurst]

Sounds like you have the fuel side well covered, have you gone through the ignition system. I had a Mini a very long time ago that behaved as you described and that was a cracked distributor cap, took me ages to pin it down. If you are not running much above idle could be the condenser playing up resulting in a weak spark and burnt contacts on the points. You says its a new engine but was it the old distributor, cap, condenser etc re-fitted or were they replaced too. Might be worth investing in a new cap, points, rotor arm and condenser. Get OEM if possible as the copies don´t always use quality materials. Won´t do any harm and shouldn´t cost much. I assuming its all nice and dry in the engine bay.
Another thing to check is an air leak in the inlet manifold/carburettor assembly that opens up when the engine gets hot, or a dodgy crankcase breather hose to inlet manifold/carb. Gets hot expands and you get a weak mixture and poor vacuum. I learnt a lot on that old mini, it was carp.

 

[spannerman]

Nor sure what type of engine you have, but it sounds like an ignition fault that is heat related. Most petrol engines take the rev counter signal from the coil negative terminal, when you crank after its cut out does the rev counter flicker? if not then the problem is on the primary circuit, ignition switch, ballast resistor if fitted, coil primary circuit breaking down or ignition module or points/condensor. If the rev counter flickers then the primary circuit is switching the coil on and off, so the fault is on the secondary (high tension) side, coil sec circuit, king lead, distributor cap, rotor arm.

 

[rafiki_]

Up, the coil or capacitor in the distributor are breaking down as temp rises. Used to be quite common on cars 30 odd years ago. Doesn't happen these days as the injection and ignition are sophisticated.

 

[jaysparticus]

Morning all,

Thanks for all the good advice, just to add - i have an electrical ignition kit on now from PowerSpark and it has the coil to match. i do believe these are intended for classic cars.

Also, yesterdays cruising issues were regardless of speed. i was cruising at 2000rpm the first time and 1600 rpm the second time??

When cruising at 1600rpm it started to splutter like it was going to stall so i upped the revs and it reluctantly went up to 2000rpm and gave me another 5-10 mins cruising until the engine just cut out without any warning?
I have a spare coil to fit which is the right part to match the engine - Ford crossflow/Watermota - its an Intermotor part. I dont think there is any issue with rotor arm or distribution cap.

Its so tough as it runs beautifully for 30mins and then just gives up , it has totally knocked my confidence in boating, especially when you break down in york where the spectators are having a good old giggle at you!

I think i may change the coil this morning and run the boat at low revs tied up to the key and see if the same thing happens, do you think this is a good idea?

 

[rafiki_]

Have another look at the distributor cap. Minor cracks can worsen with heat, causing the spark to track and reduce the power at the spark plug. Plug leads can also break down with temp too.

 

[jon and michie]

Up, the coil or capacitor in the distributor are breaking down as temp rises. Used to be quite common on cars 30 odd years ago. Doesn't happen these days as the injection and ignition are sophisticated.

Definitely sounds familiar - I drove an old mk3 escort back from Holland many years ago and would splutter and conk out every 30 - 40 minutes, stopped for 10 15 minutes and would fire back up and ran fine for the next 30 -40 minutes.

 

[gordmac]

When it stops have you checked to see if there is a spark? You can get things to go between plug and lead that show when the plug is sparking, these things:
http://www.screwfix.com/p/laser-ht-...8_1438592614_1861f687a0de86d27def29ca5ed87d20

 

[fisherman]

When my car did this it was the flywheel sensor. If you have one, check the wires.

 

[jaysparticus]

Ok guys i have had a development!!!
Thanks to everyone who is sticking with this!

What i have done this morning is go and change the coil on the boat. i have checked the distribution cap and rotor arm and they are brand new and show no signs of damage - to be honest the coil looked brand new also but with it been a sealed system i decided i would try that first.

The engine ran perfectly for 55 mins and as i was on the phone to my wife saying "i think we have cracked it!" the engine started to lull and in no rythm it started to drop revs a little. i have attched a video of this on the rev counter so you can see.

https://www.facebook.com/video.php?v=10205888373147093

the lulls then started getting more and more so i knocked it out of gear and the engine stalled. i decided to follow instructions provided above and see if there was a spark after the stall. when i removed the spark plug from number 2 chamber i inserted my gunston colour tuner so i could see a spark and low and behold there was a spark and to be honest - the engine nearly started!

when i checked the spark plug i noticed that there was a crack up one side and down the other and that end was bent ! see picture:

Do you folks think that this one spark plug may be expanding and stopping sparking as it get a bit of use?? and thats why it stalls? maybe this is why it wont restart straight away until this has cooled?

Have i finally found out the problem!!!!

 

[fisherman]

Yes. Maybe. Bet it's more than one thing. Why is it taking 55minutes. To be sure look to see if the spark is escaping via the crack to the block when things go wrong. Or just replace and try again.

 

[jaysparticus]

i think that is gonna be the best bet . i have just read that if your engine constantly misfires then it can damage the coil so maybe i have replaced the coil today and it has run without the spark on the chamber2 and damged the coil again?

 

[BruceK]

All the symptoms you describe sound very much like coil breakdown as previously mentioned, have you tried a resistance test across the coils? That will tell you if you definitely have a problem, but I've has Gills coils before that measured OK and yet were a problem. i.e. a resistance test will tell you if you have a problem if the correct readings are not measured but not neccessarily a bill of clean health if they do. But tbh it could be anything. Don't write off fuel. Sticky floats, incorrect float heights etc can all cause issues as the motor warms to operating temp and it sounds like your boat is operating slightly below temp (30 - 40 minutes at low revs) which is not uncommon in raw water cooled boats either. Good luck either way.

 

[jaysparticus]

OH Dear BruceK

i thought i was narrowing it down but as you say it could be anything.
i will have to systematically change things and use the art of illumination to try and solve it. i am not very good with a multimeter either so wouldnt really know how to check the resistance of the coil

 

[BruceK]

Sorry. When the problem occurs check for spark. If you have spark across all plugs check that they are not wet, or conversely, not lean. The plug you show, looks wet to me. If your fuel float is too high you will run well while cold, flood when hot. The resistance across the plug gap will also change according to stoichiometric ratio and heat so just checking the plugs when running normally is no guarrantee, you must do it at the point of failure. That cracked plug may well work under light load but fail under heavy load and be the end of your problems with a bit of refinement on mixture (you mentioned playing about with that?). What coils vendor and part number do you have? A google search may yield the test values.

 

[jaysparticus]

Hi Bruce, above is a picture of the plug as it first came out of the block for reference.

the coil i fitted today was an Intermotor INT 11111, The one i removed was an ACCUSPARK ?? for classic cars.

the carburettor is a twin webber carb but that is all i know. it opens one side and squirts fuel on acceleration and the other side opens upon further acceleration but doesnt squirt fuel? i have only done this when the engine is off to see if it is receiving fuel when it stalls.

i did check for a spark as soon as it stalled using the glass spark plug assembly and sure ebought there was a good spark in the chamber

 

[steadyeddy]

Had a problem with a Ford spent hours tracing the fault ,it was a sticking needle valve ,replace the needle and seat very cheap fix well worth a try.:encouragement:

 

[BruceK]

If you've eliminated spark it must be fuel then. Just double check you are using the preferred spark plug first.

 

[jaysparticus]

BPR6ES are the right ones for the MK2 Escort which i believe the 1.6 crossflow engine represents.

if its fuel then do you recommend removing the carb and getting it looked at professionally ?

its strange how it runs sweet for 50 mins then starts missing every so often? would a fuel problem symbolise this also?