Backfiring :(

[serenitycamper]

Our bus hasn't been started for two years and run up to temp, but I'm changing the coolant so that exactly where I'm at now. She's backfiring on almost every rotation and I can't rev her hardly at all.
Temp
Gauge is 1/4 of the way up and I'm following Brickwerks method.

She's never done this before any ideas?

Cheers

[BOXY]

Is the petrol 2 years old?

[serenitycamper]

I imagine a lot of it is. According the fuel gauge it has quarter of a tank of fuel. However the other day when I fired it to check out the electrics for a few seconds it spluttered, died and wouldn't restart. So I bought 5 litres of fuel and stuffed it in. It then started fine.

It is tapping quite badly as I assume the lifters have drained but I've read on the samba that after a decent run this will be sorted out. Could the tappets have anything to do with the misfire?

It only began to misfire when the temp gauge was near quarter on the gauge. Nothing before it got warm.

[serenitycamper]

Anyone??

[CovKid]

Sounds like it just needs running up to temperature and driving. Fresh oil would help. If you hadn't been started for two years, you wouldn't be too happy either.

[Choppski]

Have you checked the spark plugs, wiring, fuel flow, timing (I know the engine is still cold...), check dizzy and rotor are not furred up?

[kevtherev]

in two years a lot could happen.
The fuel pipes would have rotted inside and the crap makes its way to the carb.
The electrical contacts and joines are corroded.

backfiring is caused by many issues.
timing
fuel mixture .. weak
weak spark/no spark/intermittent spark.

you need to work through your problem methodically.
start with fuel delivery.
clean fresh and plenty full with new filter.
move on to a cleaned, fully working carb and autochoke.

any other way is guesswork imho

[serenitycamper]

Ok I'll check and clean all the electrics; cap, arm, plugs. All fuel hoses are new. Where is the filter? What do you suggest for cleaning the carb?

Also please note. There is NO BACKFIRE AT ALL when cold. Only when reaching 1/4 on the gauge. I guess when the auto choke is off.

[jimpainter]

I think the carb is probably gummed up, if it runs ok cold the choke will be on so running richer, once the choke is off it's relying on the idle/main jets but if they are partially blocked it will be running weak or no fuel at all. Of course it would be worth doing a full service, replace fuel filter near tank, drop tank to drain it, swill it out with fresh fuel to remove any crap, check timing etc etc. if it sounds tappy it will just need a good drive to pump up the lifters again.

Jim

[ghost123uk]

Yes, I bet this is another case of fuel containing Ethanol gumming jets etc up (I try to avoid Ethanol fuel). Trouble with stripping the carb to check/clean this is you need to source a carb top to base gasket

[kevtherev]

Ok I'll check and clean all the electrics; cap, arm, plugs. All fuel hoses are new. Where is the filter? What do you suggest for cleaning the carb?

Also please note. There is NO BACKFIRE AT ALL when cold. Only when reaching 1/4 on the gauge. I guess when the auto choke is off.

Choke comes fully off after 6-8 mins
if anything it reads like a delivery problem to me

[serenitycamper]

Well I cleaned everything on the ignition side and WD40 was applied to everything just in case if any moisture. Then I bought carb cleaner and blew out all the jets with an airline. Then applied carb cleaner as directed. Much much better but going to change the filter at the tank end next week when it's finally home.

I'll keep you posted.

[bikermike87]

Keep us posted Rich. I don't like the sound of poor "vinnie" getting such a lovely makeover and playing ill! It was always a good strong motor that one. Have you double checked the timing too (only a 5min job)? Before I had a new engine on Sonnie, it did something similiar, timing was corrected and it sorted it right out.

[serenitycamper]

Keep us posted Rich. I don't like the sound of poor "vinnie" getting such a lovely makeover and playing ill! It was always a good strong motor that one. Have you double checked the timing too (only a 5min job)? Before I had a new engine on Sonnie, it did something similiar, timing was corrected and it sorted it right out.

How do I check the timing Mike, it's something I've never done to anything!?!

You should see it now...drove her for the first time in nearly two years today!! Do you have Whatsapp? If so i can send some pics....you're going to love it..I hope!

[bikermike87]

It's that easy, even I can do it haha

I will check if I have the strobe at my dads, I'm in the northwest so could come round.

If not, I'm sure I got instructions from here, I can't all you through

Ill send a pm, I'm on whatsapp!