Stuttering Brumby

ktmtragic · Post by **ktmtragic** » Sun May 18, 2014 1:00 pm

Can you guys help please? My Brumby 92 EA81 sometimes on acceleration jerks as if the ignition has been turned off. If I back off the throttle gently the problem goes away. then when I accelerate again it may come back or continue as normal. Seems to be on an incline. Accelerating down hill seems to be OK. I replaced the rotor button and thought the problem was solved. Seems to not be the case. Your thoughts?

Silverbullet · Post by **Silverbullet** » Sun May 18, 2014 1:31 pm

I had identical problems until I found out the needle valve in the top of the carb wasn't letting enough fuel in; up any kind of incline or when accelerating the fuel level in the float bowl would drop too low. Check your float level or maybe your needle valve is stuck closed/blocked. You can check just by removing the top plate of the carb that holds the float/needle mechanism.

dfoyl · Post by **dfoyl** » Sun May 18, 2014 6:54 pm

Checked the battery terminals lately ? I had pretty much identical symptoms a while back and it was due to poor terminal contact - car would start fine, but on a straight road at anything but low revs it would cough and eventually stall out.

steptoe · Post by **steptoe** » Sun May 18, 2014 9:22 pm

or the 'blow the crap out of the fuel line trick' clear each end of each hard line and blow compressed air in one end , catch the crap at the other end. Do it with a near empty tank so you can observe any crub thoonking at the bottom when blowing the last pipe in

Wooster · Post by **Wooster** » Mon May 19, 2014 7:11 pm

Agreed- fuel issue. The best thing I ever did was convert to a Weber

M0rpH · Post by **M0rpH** » Sat May 31, 2014 2:29 am

My old mans brumby had this same issue once the engine had been put back in after replacing welch plugs.
Whether there was a vac hose put back wrong or not who knows, but the culprit was a little 2 or 3 way valve visible next to the right hand side of the aircleaner box.
It is black, about the circumference of a 50 cent piece and may have a bit of green plastic on it.
Never got round to working out what it was or why it was doing it, just removed one of the vac hoses attached to it, problem went away so then found a screw and plugged it.
If you need a pic let me know and i will see about uploading one.

Wooster · Post by **Wooster** » Mon Jun 02, 2014 12:59 pm

So what was teh outcome KTMtragic mate?

Post by **TOONGA** » Mon Jun 02, 2014 3:44 pm

Check everything electrical even the connectors to the fuel pump. how long ago were the spark plugs replaced? Leads? (check the resistance of the leads as well) dizzy cap?

Check the spark plugs as well as I have had plugs with 8000 KMs on them fail.

What condition are your fusable links in?

TOONGA

sven '2' · Post by **sven '2'** » Mon Jun 02, 2014 6:45 pm

Replace your fuel filters - you have 2

RSR 555 · Post by **RSR 555** » Mon Jun 02, 2014 7:48 pm

Another thing to check is HT (Spark Plug Leads) for resistance. Make sure they are within spec.