New to me 83 CJ8 Laredo!!

CJ7Pilot

18436572
LIFETIME
CJ-8.com Member
City
Yuba City
State
CA
#61
Well... it looks like the fuel pump is designed to run directly on the cam lobe, but it doesn't look like your cam has a fuel pump lobe on it!

Could your 258 have a 4.0 cam in it? I don't even know if that's possible. Maybe I'm just seeing it wrong. :shrug:

It should look like this:

fuel pump.gif
 

scramcraz

Basic User
City
lake jackson
State
tx
#62
The diagram captures the basic principle of the thing. I don't think you can install the pump wrong. I had a lot of pump problems until I dropped and cleaned my tank. There doesn't appear to be anything missing from your old pump. Its just old and probably full of trash. Or bad diaphragm.

Bob
 

spankrjs

Scrambler Junkie
LIFETIME
CJ-8.com Member
City
Biloxi
State
MS
#63
The diagram captures the basic principle of the thing. I don't think you can install the pump wrong. I had a lot of pump problems until I dropped and cleaned my tank. There doesn't appear to be anything missing from your old pump. Its just old and probably full of trash. Or bad diaphragm.

Bob
I had this happen once before on a Scrambler I was working on, the one I posted a link to. I never thought about that happening, but you are correct, the fuel pump was completely impacted with crud :huh:
 

spankrjs

Scrambler Junkie
LIFETIME
CJ-8.com Member
City
Biloxi
State
MS
#64
Well... it looks like the fuel pump is designed to run directly on the cam lobe, but it doesn't look like your cam has a fuel pump lobe on it!

Could your 258 have a 4.0 cam in it? I don't even know if that's possible. Maybe I'm just seeing it wrong. :shrug:

It should look like this:

View attachment 70352


You are right, it looks like the lobe the fuel pump arm is supposed to ride on is too far forward. Unless it is just the angle of the picture. I wouldn't think a cam could move that much, but maybe like you said, a 4.0 or aftermarket cam without the fuel pump eccentric???
 

CJ7Pilot

18436572
LIFETIME
CJ-8.com Member
City
Yuba City
State
CA
#65
You are right, it looks like the lobe the fuel pump arm is supposed to ride on is too far forward. Unless it is just the angle of the picture. I wouldn't think a cam could move that much, but maybe like you said, a 4.0 or aftermarket cam without the fuel pump eccentric???
The lobe I see in the photo has a lifter sitting on it, so that's the angle of the photo. Right behind it (to the left in the photo) is where I would expect to see a nice shiny fuel pump eccentric lobe... but all I see is an unfinished part of the camshaft. Weird.
 

don87401

Scrambler Junkie
LIFETIME
CJ-8.com Member
SOA Member
City
Farmington
State
NM
#66
Here are pictures of my original 258, the cam is not original, it is a Clifford Cam.


This is fuel pump lobe.
20190227_103845.jpgresized.jpg

This is the lifter lobe to the right of the fuel pump lobe.
20190227_103851.jpgresized.jpg

This is the lifter lobe to the left of the fuel pump lobe.
20190227_103901.jpgresized.jpg
 

jammer1

Scrambler Junkie
LIFETIME
CJ-8.com Member
City
Maple Hts.
State
Oh
#67
Believe it or not, I had to replace a fuel pump. I made the mistake of angling the pump arm up when installing the pump. The arm was riding on top of the cam. It felt tight when installing and I needed to use the bolts to bring the pump against the block. Tried starting and it wouldn't start (never realizing what I did). Pulled it apart and figured it out. I was lucky I didn't damage the cam lobe. Put the pump in the correct way and it ran fine. My first build when I was 20. I felt like a idiot then and now. Maybe the previous owner did the same thing, didn't figure it out and went the electric pump root?
 

jammer1

Scrambler Junkie
LIFETIME
CJ-8.com Member
City
Maple Hts.
State
Oh
#68
Second thought it looks like he's missing the lobe. It looks like it was riding on the shaft. Could someone have changed the cam to one that is made for a electric pump.
 

jammer1

Scrambler Junkie
LIFETIME
CJ-8.com Member
City
Maple Hts.
State
Oh
#74
The pump is in the wrong place. Electric fuel pumps are pushers, not pullers. It should be as close to the tank (or in the tank) as you can get. Nice fuel line. What a mess.
 

CJ7Pilot

18436572
LIFETIME
CJ-8.com Member
City
Yuba City
State
CA
#78
Well, I don't think anything fell in to your oil pan... I think it's pretty evident that someone installed the wrong cam! :shrug:

No sweat though, it's not that big of a deal to keep running an electric pump for a while.

Heck, you might decide to install fuel injection, and the mechanical pump would end up being useless anyway!

You can get a plate to cover that hole, and leave the fuel pump off. That might help avoid confusion for someone in the future.

Have fun! :cheers:

Edit: Like ag4ever mentioned, it would be a good idea to relocate that electric fuel pump. :wave:
 

bryrambler

Legacy Registered User
City
Tenafly
State
NJ
#79
Wow! Crazy! Yeah the electric pump works. It just needs clean gas to pump. And I do want to install fuel injection! I wanna research a bit but I was thinking of going that rout. But until then where should the pump be put along the line... I think he mentioned closer to the tank..?
 
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