Ignition or Fuel issue

1959 - 1978, M151, M151A1, M151A2, Technical questions and discussions, regarding anything related to the M151.
Post Reply
bharr
G-Sergeant First Class
G-Sergeant First Class
Posts: 83
Joined: Wed Sep 17, 2008 1:23 pm
Location: NC

Ignition or Fuel issue

Post by bharr » Tue Jul 04, 2017 8:49 am

Started my 67 M151a1 for the parade today. Normal startup and then as I started going down the road it started missing. When I gave it full acceleration, it sputtered and then seemed to run smoothly until I let off and then seemed to miss again. When I came to any inclines, it seemed to miss, again full acceleration, it sputtered and then ran smoothly. I run premium non-ethanol fuel. Any ideas? Thanks in advance.
Stupid is free so it's everywhere !!


Rickf
G-Lieutenant General
G-Lieutenant General
Posts: 5909
Joined: Sun Mar 19, 2006 10:04 am
Location: Pemberton, New Jersey

Re: Ignition or Fuel issue

Post by Rickf » Tue Jul 04, 2017 11:23 am

Sounds like the accelerator pump diaphragm has gone bad. and it will run better on regular gas instead of premium, but if the diaphragm is bad then it will stumble every time you hit the gas.
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone

bharr
G-Sergeant First Class
G-Sergeant First Class
Posts: 83
Joined: Wed Sep 17, 2008 1:23 pm
Location: NC

Re: Ignition or Fuel issue

Post by bharr » Wed Jul 05, 2017 6:37 am

How difficult is it to replace? I use premium because that is the only non-ethanol I can find in my area.
Stupid is free so it's everywhere !!

Rickf
G-Lieutenant General
G-Lieutenant General
Posts: 5909
Joined: Sun Mar 19, 2006 10:04 am
Location: Pemberton, New Jersey

Re: Ignition or Fuel issue

Post by Rickf » Wed Jul 05, 2017 6:52 am

Understood on the gas, the diaphragm is pretty easy. It can be done without removing the carb if you are careful. You will see four screws on the side of the bowl, that is where it lives. Take out three of the screws and loosen the fourth and then hold the cover in and take out the fourth screw. Remove the cover but be careful because there is a spring right under the cover and then the diaphragm. A lot of the time the diaphragm will stick to the cover and hold the spring back just long enough for you to get it off and twang! there goes the spring! So as the cover comes away just be sure you get control of both pieces. Pay attention to which way the diaphragm is facing, there is a larger round metal plate that the spring sets in and that has to face out towards the cover and the vacuum hole has to line up with the hole in the carb and the cover. The problem is that you are going to have to buy a carb kit to get the diaphragm. As long as it is running good otherwise I would suggest just getting a small kit from one of the surplus dealers, you do not need to spend all the money on a large kit that you will not use most of.
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone


Post Reply

Return to “M151's Technical Knowledge Base”

Who is online

Users browsing this forum: No registered users and 35 guests