Cabrio works well but plagued by mysterious non-starting problem

[rmusker]

So it has now been four months since I bought the Cabrio. After a few niggles that were resolved the one thing that I cannot seem to be able to resolve is the fact it will not start in the mornings or when the engine is cold. I have changed the HT Leads and coil. I have had the Weber 28/32 Carb checked - the auto choke works fine and the carb was fitted around 2019. The Engine is a Sierra Mk2 1985-1991 EFI Engine 2.0l DOHC 8 Valve
The plugs are fairly new. I am now reduced to spraying easy start down the carb and most of the time she starts. Sometime whilst cranking a spray of petrol can be seen being pushed out of the top of the carb. When she is running all is well - other than when pulling away the engine momentarily bogs down. Will another tap of the throttle and all is well but this may be associated to the problem - whatever it is. When I first got the car she started OK but over time starting has been an issue when cold. The season has changed from summer to winter but other than that I struggle to work out what the problem is. Any tips or suggestions would be much appreciated - anyway - all Marlin Owners, have a very Happy Christmas

[terryrscott]

I had a similar problem with my cabrio after changing loads of parts it turned out to be the mechanical fuel pump.

[jon_cox]

Hi
First of all check all electrics are good. High voltage circuit etc. If not all ready fitted get an earth strap directly from engine block to battery terminal. Is the coil correct? Some have ballast resistors and some do not. If yours is ballast then make sure the cranking voltage is correct. Then fuelling. Take off pipe to carb and see how long it takes for the manual pump to pull the fuel through from the tank or fit a fuel filter and watch this for flow. It does not take long for all the fuel to syphon back to the tank. Fit an eclectic fuel pump designed for engine bay positioning and low pressure for carbs. I have a Huco pump fitted and works great. If you fit the electric pump then please make sure you also fit an inertia switch / relay in case you have an accident. Safety first.

[rmusker]

Thanks for your suggestion = all very useful. Investigations will commence!

[rmusker]

I have been told easy start is verboten so to that end I took the top off the air filter this morning and pushed the choke butterfly to one side so I could see down into the carb and operated the accelerator linkage. I could see droplets of petrol being pumped out so I tried staring it and off she went! We are getting there!

[rmusker]

At long last the non starting when cold problem has been solved. After several requests for me to stop using easy start from the forum and FB I was looking round the carb trying to prime it prior to starting it. I worked the accelerator cable and saw the little arm at the side of the carb going up and down to pump fuel into the manifold. I then noticed there was quite a bit of slack on the cable and noticed that the locking nut on the outer cable adjustment was lose. It seems that over a period of time the outer part of the cable had been revolving and winding itself shorter, thus making the cable longer which meant that when the accelerator pedal was fully depressed there was too much cable and therefore the priming pump was not operating. This would explain the gradual worsening of the non starting as the cable slowly shortened. I have subsequently wound out the thread on the outer section of the cable, making the accelerator cable shorter. The fuel priming pump now works and she starts from cold every time.
If all this is a bit muddling I have attached a picture.
Thanks for your help - I would not of delved into the engine bay otherwise
Happy ChristmasCat.jpg
Rory