4 replies to this topic

[kiwimike01]

I've got a 998 Im sure with a hs4 carb. It'll start with a bit of help down the air filter. When it eventually starts with the choke right out it'll idle high then as it warms the choke can be let off but it'll idle rough like a lumpy sound to it then as I adjust the the carb jet to richen the mix the revs spike then drop down. Also when I try accelerate to get it to rev higher it starves the engine and dies. It also makes a big sucking sound when accelerating so guessing its just all air and no fuel.
The carb was pulled apart and cleaned making sure to not damage the needle. Put back together with new jet assembly as the old one was leaking fuel all over the exhaust and new dash pot oil.
Also have replaced coil, dizzy cap, leads and changed to electronic ignition
Please help I'm losing faith...

[cal844]

Sounds like the fuel pump is the fault here.
Remove the fuel pipe at the carb, get a bottle or container and crank the engine over, does fuel come out the pipe?

Edited by cal844, 24 April 2019 - 09:56 AM.

[kiwimike01]

Will give that a go today and get back to you. Thanks for the suggestion

[kiwimike01]

Pulled the fuel line off at the carb and cranked the engine over. Big spurts of fuel came out at regular intervals so don't think it is the fuel pump.

[kiwimike01]

Could it be a leaking gasket between carb and intake manifold? Possibly sucking air through a hole and bypassing the fuel and choking the engine with air then when butterfly closes it goes back to normal air fuel but with the excess fuel that was not sucked into the engine finally going it causing the revs to spike? I re used the old one because I am just trying to get it running so I can drive it to my own garage from my mums. I think I will order a new gasket kit and try that.
Is there is a way to test a leaky gasket while I wait for the new ones?