Fuel pump on 85 GW

I just looked on AutoZone's site and found a fuel pump listed for your vehicle. The Brand is Master and the part number is 6736. Price shows $13.99 using my zip code.

Chris

Thanks Bill, Chris.

Fred

Hi Group

Well I finally got the new fuel pump in. I didn't want to go in untill I got it at low cam. That's the good news. The bad news it has not fixed the cold start problem. For all of the 10 years I have had this truck you have to crank it a few times when cold to get gas to it. Comments here were to change the filter and fuel pump. Well that's done but the problem persists. Possibly the float bowl in the carb drains away when sitting a while? Any comments on that possibility or others? I wonder if that is a major job.

Thanks Fred

That is usually caused by one of two things on Jeeps.

First is the gas filter could be in upside down. It has 2 outlets, The center one goes to the carb and the top one goes to the return line. If the return line nipple isn't at the top, gas will syphon back to the gas tank when it sits.

The second reason is a pinhole leak in the line on the suction side of the gas pump. Usually the leak will be either at a clip where the gas line is clipped to the frame or in the rubber hose. Because it is a suction line, it can leak and not drip on the ground until it gets really bad. If you look close you can see a stain mark where the leak is. This will let air in causing hard cold starts.

Mike

Just thinking out loud.. :)

not familiar with your carb but on some fuel pressure pumps there is a return line and a carb supply line. If you get these two reversed then the carb will drain. Pressure regulators have check valves also. And so did my old Rochester 4M4 quadrajet (in the fuel filter), but that's not your carb.

Hi Group

Well, I checked the new filter and I put it in ok. I haven't seen any leaks in the gas lines. One note: There was lots of gas in the old filter and fuel pump when I took them out after the truck sat a week, so it looks like gas is possibly getting to the carb ok? I wonder if there is some other hose that is draining the carb of gas when it sits a day or longer? I don't see any leaks around the carburetor.

Fred

How is the choke?

On those, you are supposed to pump the gas pedal 2 or 3 times to prime it and to set the choke.

If you open the air filter and pump the gas with the engine off, does the choke close tight? If you look inside and pump the gas, do you see a squirt of fuel?

Mike

Hi Mike

Choke is fine. No squirt of fuel though.

Fred

There ya go, you have a worn out accelerator pump then likely. New ones come with carb kits.

I would also check that for a squirt when the engine recently shut down. There is the odd chance the carb has a crack allowing the accelerator pump sump to go dry, but it would be unusual.

Mike

"Fred V." wrote:

Thanks Mike

One carb kit to get! I had a hunch all along it was a carburetor problem.

Fred

Hi Group

I see the problem. Fuel is seeping out of the accelerator pump gasket area which is on the side of the carburetor. This eventually drains the float bowl which would account for the starting problem. I got a carb kit so I will tackle it.

Fred

Be sure to carefully check and set your float level and be careful with the needle valve.

Hi Group

Finished up the carb rebuild. It really needed some attention it seems. Lots of leaky gaskets. Basically a clean job. Almost fun! No more leaks so the gas stays in the float bowl and it starts up cold fine again.

One issue with the carb kit. The carburetor seems to have two gaskets under it. A smaller one right under it and a larger one between that and the manifold. The larger one looks like its main job is a spacer on my engine that makes the carb sit higher off the engine. The new kit contained the proper smaller gasket but a much thinner spacer gasket. Since the spacer gasket on the engine looked in perfect condition I reused that one. The new gasket would have changed the carb height. That didn't sound right. Running like new now. Fred

Fred,

Back in my drag racing days we tried all sorts of 'tricks' to get an edge in performance.

One of those was spacers between the carburetor and manifold for two reasons heat insulation and addition space for vaporization.

One thing is certain.... an awful lot of problems were caused by improperly set floats and improperly balanced venturi.

It surprises me sometimes that guys with the older Jeeps live with their carburetor problems....sometimes they are stuck because they live in a socialist run state (like the kommunist koalition of kinky kooks and knotheads of kalifornia) that go spastic if you want to make a change to make your vehicle run better and pollute less..

Rebuilding carburetors used to be something that was commonplace and done regularly but I guess that all the people who knew how are probably retirement age now...

Carbs are fun. :]

The larger one is just a thermal barrier to keep the fuel in the carb from getting cooked by the intake rail heat. I'd probably spray a bit of carb cleaner around the base just to make sure you don't have any leaks.