Jump to content

engine loses prime over night


Recommended Posts

i dont know how to search the archives i guess, but my old 77  2 valve loses prime over night, a little ether helps but dont sound to good on motor. i cant find any leaks and have changed both filters.  i would consider a electric pump tp prime with but dont see a good way to tie it in.   stumped?

Link to comment
Share on other sites

NO ETHER!!!!   There may be an issue with the lift pump on the side of the injection pump...  The electric pump is something I would do on my stuff just to see if it helps, etc...  hell try it,  but there should be a functioning check valve in the lift pump... Post a pic of the pump, I'm curios. I assume an Ambach,  Jojo

  • Like 2
Link to comment
Share on other sites

I just went through this on a 96 em7-300 fully mechanical. Threw a bunch of parts at it including new lift pump and fuel lines etc.  It ended up being the little jumper between the heads for the return fuel. One of the fittings was a little loose. Problem solved

Link to comment
Share on other sites

As I have mentioned many times before, if your loosing prime when the motor isnt running its the return to the tank side of things 

 

Pressurise the fuel system to maybe 10 - 15 psi at the fuel cap on the tank and look for leaks

Do this before you start blowing a whole of money buying parts hoping to fix it

All these check valves and things always leak back with a little bit of age, the return fuel line siphons fuel back up from the tank to keep it primed when it isnt running, old mechanical injector pump motors are desgined this way

Need to remember millions upon millions of diesel motors have been built with the same basic injection system and dont need a electric fuel pump

 

Good luck

 

Paul 

Link to comment
Share on other sites

thank you guys for info on stuff to look at,   im old and old school and cant put picture on cause i still have a flip fone. my brain refuses to update and thats part of the reason i still drive a 77 r model, i guess me and the old dump truck understand each other, at least we did before this latest curveball.

Link to comment
Share on other sites

Get a piece of bicycle tube with the valve in it,clamp one end tight clamp the other end around the fuel tank fill,air it up and leave it for a while,if there’s a leak you’ll find it..

Link to comment
Share on other sites

Thats pretty much what I do, one thing to remember is the tank will most likely be vented so I just  wind the regulator right back and leave it on

Apart from the obvious problem of over pressuring the tank which wont happen as the tube will pop off, the regulator allows you to leave the air connected and walk away and look and study etc 

 

 

Paul 

  • Like 2
Link to comment
Share on other sites

1 hour ago, Joey Mack said:

The inner tube tool is an awesome idea, mind if I use it to fix my own junk??  😉  Jojo

Don’t mind at all,even trade for all the help I’ve gotten from you..

  • Like 1
Link to comment
Share on other sites

  • 2 weeks later...
On 6/28/2021 at 5:55 AM, mrsmackpaul said:

As I have mentioned many times before, if your loosing prime when the motor isnt running its the return to the tank side of things 

 

Pressurise the fuel system to maybe 10 - 15 psi at the fuel cap on the tank and look for leaks

Do this before you start blowing a whole of money buying parts hoping to fix it

All these check valves and things always leak back with a little bit of age, the return fuel line siphons fuel back up from the tank to keep it primed when it isnt running, old mechanical injector pump motors are desgined this way

Need to remember millions upon millions of diesel motors have been built with the same basic injection system and dont need a electric fuel pump

 

Good luck

 

Paul 

found leak behind fan on return using 12 lbs in tanks    thank you

  • Like 1
Link to comment
Share on other sites

Great!!!  I tuned a skipping, E-6, 2 valve today, my customer was very happy...  we need to keep these great machines running....  jojo

  • Like 1
Link to comment
Share on other sites

It was easy,  popping through the exhaust, and poor revving, and a lot of smoke.     I cooled it off and ran the valves,  #6 was wicked tight...  cranked it and it Purred like a Dog.... I did raise the idle speed to about 600... .. Jojo

  • Like 1
Link to comment
Share on other sites

How much is the pressure typically on the lift pump on a cs-200/250 milliner? Mines been hard to start I guess it’s been bleeding down too !

also,ran out of fuel sitting at shop,now won’t restart, not pulling any fuel over , it’s not been run in a good while

i opened a couple injector lines to bleed it, not helping

help !

Link to comment
Share on other sites

Join the conversation

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

Guest
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.

 Share

  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...