4 replies to this topic

[GTRMikie]

I have just rebuilt a 998 engine. It is fitted with the HIF38 carb and needle that it had prior to rebuild. The engine starts and runs fine, apart from one problem. When the throttle is blipped, the revs rise then fall back beyond the idle rpm, the engine almost stalls before it settles to a smooth idle. If the revs are increased then allowed to drop in a controlled manner, there is no attempted stalling. Ive tried various grades of oil in the dashpot, to no avail. The carb piston does not appear to be sticking, any ideas?

[ukcooper]

get a can of wd40 and spray it around the manifold etc and see if the revs change , your tey to creat a gasket with the wd40 to see if there an air leak anywhere

have you reboard changed exhaust or such likes it if so ya need another needle

ps wd40 is flammable so be careful

Edited by ukcooper, 23 March 2018 - 01:15 PM.

[Retroman]

Was the engine upgraded ?

[GTRMikie]

No upgrade apart from unleaded valve seats.

[Retroman]

Ok it sounds like it needs a tune up, clean the carb internals, make sure the needle is set correctly, a few drops of clean oil in the carb damper, set tappets, plug gaps, points (?)

 

Has it got fresh petrol in...?