Suffolk Punch 35s Fuel problem (Delloro Carb)

scallywag65 · 31 Aug 2019

Hello everyone, hope someone can offer some advice on what is causing Fuel not reaching the Combustion chamber.
Filled up with new Fuel, drained out all the old fuel from Tank, Pipe, and Carb.Removed all the Jets and cleaned them out but they all seemed to be clear.Cranked it over a few times and no start, so removed Plug to see if the Plug had Fuel on it and it was totally dry,so put a small amount of Fuel in Spark Plug hole,cranked it over and it fired up and run for a couple of seconds till it had burnt the added Fuel, so can anyone tell me what would be stopping the Fuel reaching the Chamber, would appreciate any advice offered, thank you for looking.

Nige F · 31 Aug 2019

You may find it's simply the float valve pin stuck or blocked. If you're not going to use the mower( over winter) you could take the carb off and soak it in a sealed jar of methylated spirits over winter - that'll dissolve all the deposits from the unleaded petrol - then dose the fuel with stabiliser to preserve it over winter

Burnerman · 31 Aug 2019

This will be the black painted engine, I think?
Press the spring loaded float drain button on the bottom of the float bowl, and see if fuel runs out.....if it does the float valve is working. The carb may be a FCH 20 perhaps but I haven't seen one for years.
If that's ok, then its float bowl off, followed by the main jet and the emulsion tube above it.
Set the idle fuel screw to 1 1/2 turns out to begin with, apply full choke and try again!
John

scallywag65 · 1 Sep 2019

That,s right, the black painted engine. Fuel is getting into the Bowl and i,ve cleaned all the Jets inc the main Jet, although i don't recognise any emulsion tube above it!

Burnerman · 1 Sep 2019

The brass main jet is unscrewed and if you peer in where it came from you should see another brass tube, which is called the emulsion tube. This is hollow but with side drillings to help vaporise the petrol as it is sucked in. If it doesn't fall out then slight tapping usually dislodges it from its housing.
Also check for a side drilling into the main jet housing - that must be clear.
What I'm saying here is for typical carburettors - its so long since I've seen this Dell Orto that I may be talking rubbish but its worth a look see anyway!
Always clear the drillings with an aerosol carb cleaner and compressed air if you can.
John

scallywag65 · 1 Sep 2019

Thanks for that John, that might be the only one i hadn't found and cleaned, will try again when i get some carb cleaner later, thanks again.Phil.

scallywag65 · 1 Sep 2019

Well, what i have is an Idle Emulsion Tube-Main Jet (as described in a blow up diagram of the Carb) this unscrews from the centre of the main body of the Carb and screws in approx 6mm lower than the housing for this Jet, once unscrewed there is a hole where the male part of the end of the Jet sits, as mentioned, this Jet screws in and will not come out as you suggest by falling out or tapping it, and you,re right it is an FCH 20 Carb and am now looking for a 2nd hand one as i,ve exhausted all options as far as the Carb being the problem, thanks again for your help.

Burnerman · 1 Sep 2019

No worries Phil, hope you find one.
There isn't an issue with the throttle linkage is there......the engine won't like to start if it is set to idle.
John

scallywag65 · 1 Sep 2019

Good news John, just had another look at the Linkage etc and it didn't seem to be moving when opening/closing Throttle so had a play with it and adjusted it so that it moved when operating Throttle....then gave it a few pulls on the chord and nothing, so removed plug and it had Fuel on it and some in the Chamber, so carb was ok at last and had another few pulls and away she went, just wanted to thank you for taking the time to advise me on this really frustrating problem. Cheers Phil.

Burnerman · 1 Sep 2019

Result!

Well done for persevering with it, and hopefully you'll get years of service.....just keep an eye on the oil level.
John

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Suffolk Punch 35s Fuel problem (Delloro Carb)

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