My 75 dodge 360 Motorhome wont start sitting too long

I have a 1975 doge sportsman cobra motorhome with a 5.9L 360 2 barrel engine in it. Its been sitting approx 8mon. Prior to the 8mon it started just fine. So im pretty sure this is just due to it sitting. Any suggestions?

Try adding a small amount of gasoline to the engine thru the carburetor, and then try starting it.


That was my first thought but thats kinda dangerous i was hoping there might be another way.

That’s how you prime an engine with a carburetor.


Ive never had to actually do this before. Cross ur fingers. Lol

If you are uncomfortable about the gas in carb then if you have a motorhome service center near you they usually have a mobile repair service. It is not cheap but should be less then your deductible should you mess up and start a fire.
Any chance you are a member a road service club?

1 Like

No but im about to be. Thank you both for ur advice its very much appreciated

Well i put the gas in the carburetor and went to start it up and now it barely wants to crank up and makes a hissing noise before shutting down completely.

How much gas did you add?


A half spray bottle cap

Its the hissing noise coming from the front of the engine is the culprit

When i turn it over it acts like the battery is dying then as it shuts down the hissing noise starts and lasts for about 2 to 3 seconds

Could it be a hose?

The hissing is probably compressed air/fuel leaking from a not-quite-closed valve, and does not indicate a problem.

I used to pour about a tablespoon of fuel into the carb of my long-sitting 1979 Toyota truck, the replace the air cleaner cover and start it up. Your larger engine might do better with more than that. Is the engine turning over at normal speed - that would indicate the battery and its connections are OK.

I almost forgot…the 3 screws on top of crb i removed then put bck did tht possibly be affecting the issue

It will turn over but before starting it shutdown and cts luke its the battery dying

Charge the battery.

I have a ford truck of similar vintage. 302 v8. If I let it sit too long sometimes the carb treatment described above works; i.e. ,squirting a couple tablespoons of gasoline directly into the throat (air intake) of the carb. If that doesn’t work, then I have to pop the top off the carb and fill the fuel bowl with gas. Sometimes even that doesn’t keep it running, the fuel bowl just gets empties and it dies. Then I have to diddle with the fuel inlet valve on the carb, as it sometimes get stuck in the closed position. Usually by then it is running , or I’ve rented another truck … lol …

I got tired of doing all that, and now I drive my truck on a trip of at least 5 miles a couple times a week. It’s much less cranky when it gets out and about to see what’s going on in the town.

re the hissing. The carb itself will make a quite noticeable hissing noise if you run the engine with the air cleaner ass’y removed. You’ll hear it more when temporarily bumping the rpms from idle. That’s just the air rushing into the engine past the carb’s venturi and throttle valve. Normal in other words.

BTW, best not to run the engine with the air cleaner ass’y removed. Even a tiny speck of dirt can get sucked into and clog one of the carb’s bleeder ports. If the engine seems to be idling fine for 10 minutes, then it suddenly stalls and won’t start, that’s likely what happened. That can require the carb be rebuilt to get it to run again.

You might remove the top of the air cleaner, hold the choke flap open, and look down the carburetor throat as you operate the carb linkage by hand. You should see gasoline spraying from the acclerator pump discharge nozzles each time you open the throttle.
If there is no gas then something has plugged up the pump circuit.

Rod Knox is exactly right about a speck of dirt affecting the carb. Back in the late 80s I overhauled a Subaru carb and the owner flat refused to spend a few bucks extra to replace the fillthy air filter. I spent 5 minutes telling him that could be a problem but he wouldn’t listen.

The car left running like a top. Two weeks later it was back on the tow truck. The cause? A piece of debris from that nasty air filter came loose and just happened to wedge in an air bleed. He tried to blame me but I told him to re-read his copy of the repair order which plainly stated I wasn’t responsible if the air filter caused a problem.

The hissing could be a sizeable vacuum leak and that can cause a no-start or rough running condition. Rod Knox is also correct about this being the sound of incoming air through the carburetor.

1 Like

I found the problem. It ended up being my battery was bad afterall. Now my problem is getting a new one. This thing costs $276 at autozone for a D34.
But do i have to use this same model battery or can i use a cheaper one?