Acceleration Flat Spot

Discuss MEL Engine Stock Carburetor Topics
Post Reply
john116
Airman basic
Posts: 7
Joined: Wed 18. Nov 2009, 15:07
Gender: male
Music instruments you're playing: Piano

Acceleration Flat Spot

Post by john116 » Mon 7. May 2012, 23:11

Hi All,
Just a carb question - my 58 Mercury with 430ci engine and stock 4BBL carb has a flat spot on accelerating from idle. I know this is a classic faulty accelerator pump symptom, however, I checked the accelerator pump diaphragm and it seems to be intact. When watching down the throat of the carb, minimal fuel gets ejected from the accelelerator pump jets on gentle acceleration. A decent quantity only comes out on moderate to hard acceleration.
Thanks guys.
John

User avatar
Theo
Administrator
Administrator
Posts: 1209
Joined: Sun 21. Dec 2008, 14:10
Gender: male
Location: Berlin / Potsdam in Germany
Contact:

Re: Acceleration Flat Spot

Post by Theo » Wed 9. May 2012, 01:46

Had a similar problem until I found out that the fuel bowl was dirty w. metal flakes and other debris. These particles can get between the needle and the seat. Anyway you might check this first before you burn out your brain ;)
Best regards
Theo
Admin

User avatar
Shelby#18
Master Sergeant
Master Sergeant
Posts: 366
Joined: Fri 17. Apr 2009, 14:15
Gender: male
Music instruments you're playing: none

Re: Acceleration Flat Spot

Post by Shelby#18 » Wed 9. May 2012, 09:58

How about the fuel pump shaft being worn? It would be a quick check to disconnect the hose after the fuel pump to see if it is pumping out the correct volume.

Post Reply

Return to “MEL Engine Stock Carburetor”

Who is online

Users browsing this forum: No registered users and 3 guests