D180 back firing when throttled up

[Donellis 1]

I just bought a D180 and when throttled up it back fires through the mufflers and ideas what it could be ?

[pfrederi 18,696]

If it only backfires as the throttle is being opened up then stops backfiring when the engine reaches speed I would look first at the mixture.

Does it pick up load smoothly or does she stumble a bit, that is also a sign of too lean a mixture.

  Running too lean can cause back fires back out the high speed mixture a 1/4 turn see if it helps.

 

Valve adjustment may be an issue but I like to try simple fixes first.

 

 

[pacer 3,177]

What Paulf says first - especially if it has been sitting up (gas now days is horrible sitting up) as he said a quick tweak on the carb might tell you something.

 

But, this could be a bit of a pill to chase down - could be several different things. Next would be ignition, point gap could be off (set at .018-.020) and they could have oxidized and the plugs could be getting bad, again, especially if been sitting - since its 'new' you probably oughta get new plugs & points anyway so you'll know how old they are.

 

Back to carb and gas, if been sitting it will get really nasty and mean the carb will have to be cleaned, here again, you might want to ck out the whole fuel system, the old gas is murder on fuel lines and filters - and gumming up the tank!

 

 Oh, and by the way, if you fall in love with your 'new' Big D' like I am then you gonna have some fun (I've got 3 of em!!)

Edited May 9, 2017 by pacer

[Thisguyisnew 114]

likely your air filter was never replaced and carb was adjusted on until it stopped running well before it sat. Set it back to factory and then dial it back in with procedure in manual.

Edited May 9, 2017 by Thisguyisnew

[953 nut 60,137]

I would suggest starting with a new gas line, filter and fresh gas with Seafoam additive, Also, new spark plugs and air filter.