Jump to content

1973 237 engine fuel problems

Recommended Posts

Hello friends! I hope everyone is doing well, it's been a while. Started haveing some trouble with the 1979 RD685S dump truck that has a 1973 237 engine. Once it sits a while, it'll start right up run fine for a few sec and go dead. After that it's very hard to start to the point of draining batteries. But once it starts back up it'll run all day and restart with no problem until it sits for a day or so. It does have new filters. Any tips would be appreciated!

Link to comment
Share on other sites

Most fuel systems have a check valve on the supply side, I suspect it is located in the lift pump. I am sure someone on BMT is more knowledgeable than me. If I am wrong someone will hopefully correct my mess.

Could also be a bad "seal" on the fuel filter.

Either way it sounds like the fuel system is losing "prime" when sitting for extended time.


PRR Country and Charter member of the "Mack Pack"

Link to comment
Share on other sites

Sounds close to my problem. Though, I never touched my filters before my problem.

As other has said sounds like you are loosing prime from the pump to the tank. I would unscrew the new filters and clean the seal and the face of the filter mount to ensure there is a tight seal. Any air between the tank and lift pump and you will lose prime. It is also possible that perhaps the primer handle will let some air into the lines as well, my primer handle on my 673 will bubble and leak a bit of fuel when priming. Though I would look at the filer seal first.


What America needs is less bull and more Bulldog!

Link to comment
Share on other sites

Thanks for the tips! I'm very suspicious of the fuel filter now that you mention it. Seems it all started shortly after I replaced them, but I also filled the tanks completely up probably for the first time in a while. Was thinking some rust might have give me some trouble, but it runs to good when it starts. Its definately loosing prime as it sits. Never had that to happen on a fuel filter. I did look for fuel leaks and didn't notice any. I'll look into it and let you know.

Link to comment
Share on other sites

Going to have to wait until I can get extra filters. I let a local mechanic I've used before service the truck and he installed the filters. They are on so tight that I'll probably damage them trying to remove. This makes me think even more that the seals could be pinched or rolled.

Link to comment
Share on other sites

  • 2 weeks later...

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Recently Browsing   0 members

    • No registered users viewing this page.
  • Create New...