Talk Morgan Forums Morgan Sports Cars Morgan Three Wheeler & Super 3 Engine cutting out, difficult to hot start.

Hello Everyone,
Have been having a few difficulties, done lots of reading of previous posts but can't seem to find a solution - so thought I would ask the collective.

Recently ran my M3W for 210 miles prior to refilling. Chose high octane 97RON.
Car ran for another 7 miles & then started missing and backfiring, eventually coming to a halt. Restarted ran another 1/2 mile and then ground to a halt.
When the engine cooled it restarted but ran less well, but took me within 2 miles of home. Eventually I got recovered home.
I was able to check that we had fuel at the injectors (by removing the pipe) & a spark, I can also confirm that the fuel pump goes through its priming process each time I try to start it. However I was not able to smell petrol no matter how many times I turned the engine over.
On looking around the engine I noticed a small drop of oil on the bottom of the air filter cover. On checking - the air filter was totally black and clogged, I could also see that one of the HT leads was split where it shrouds the plug.
I fitted new plugs, ht leads and a new air filter - started instantly & ran very smoothly, producing a clean and clear 'pop' from the exhaust - I thought that I had fixed it, so this weekend summoned up the courage to try it out
The car ran really well for 35 miles, much cleaner and more responsive, however when I got home I turned it off whilst I reopened the garage.
Would not re start, turns over OK, could not smell any fuel - although the pump was priming. Left it standing for 20mins, started on the 3rd attempt, ran for about another 60 secs and then cut out.
Does this sound familiar to anyone?
Any help/ideas are greatly appreciated.

Thanks
Andrew

Could well be the pump isn't producing the fuel pressure required. S&S state 58psi. Best get the pressure checked, ideally with it running as the pump might be able to get almost enough pressure with the engine stopped but not when it is running.
Good luck!

Does the fuel line pass anywhere hot? It sounds like vapour lock, but I'm not sure other 3W owners have suffered from this, so it's a wild guess.

Vapour lock is the fuel evaporating slightly, through heat, en route to the injectors. The solution is to wrap the fuel line in heat protecting material - you can test the theory by wrapping the line in bacon foil.

I had a Harley that did that a while ago, it was put down to overheating by the dealer, when I got it back it still ran rough, the dealer denied anything was wrong, in the end I took it to Dynojet and had the ECU re mapped, it was transformed!!
Bearing in mind you are in the UK and its winter I doubt it can be put down to overheating unless you have recently been abroad?

Ian

Were the spark plugs black (sooty)? and had the oil level dropped?
Forgot to mention the outcome: the engine was running too lean on the lower third of the rev range, thus when pottering about at low revs the engine was getting too hot, fine if you thrashed it though, dynojet sorted out the fuel flow and it never suffered from that problem again.
Aparantly when the Harley engine gets too hot the rear cylinder (which on a Harley would be the hottest)only fire every alternate cycle, if it is still too hot it somehow allows oil into the cylinder bore to help cool it down, thus the sooty plugs.

Might be worth ruling out there are any fault codes showing on the ECU by connecting up to a laptop running the S&S protune software and looking at the audit trail.
Another thought , given you are in Ludlow give Matts machine Shop a call , I think they are about 20 miles from you. He is an accredited S&S tuning expert and might have an opinion.
Good Luck

Fuel pump..seems for me .
Put the contact And try to introduce a little pen into the valve between the cylinders if the fuel pump run Well you must have fuel under pressure.

When my fuel pump went out, the car would start and idle but not rev above 1,800 rpms. Subsequent trouble shooting showed a fuel pump pressure of 18 psi at the test port between the injectors. I also had fault codes saying that the front and rear cylinder adaptive tables were unable to cope with the reduced pressure.

Fuel pump! Check the pressure for 58#. Fuel pumps for out little darlins are a problem. I had a failure with a lot of intermittent starts, pops, and sputs, and the pressure was 22 psi. New fuel pump on the way. My first road side failure and a pain. If it wasn't so much fun------

This might be a stupid suggestion but it sounds like the classic problem with vapour lock if you fill the tank too full. Although I would have thought 35 miles was enough.