Speed cutting out... Gas issue?

[Candikane]

I have a 1984 executive, 35 footer, and when driving it will suddenly lose speed and drop from 60mph to 35mph or so. It did this and then went back up to 60 for a bit, and then again cut speed in half. First thoughts? Gas system issue?

[rojohot]

make sure that your gas cap is a vented one . i had that problem and i found out someone put a non vented gas cap on the motorhome. hopeyou find the problem

[DougE]

If you're trying to pass or going up a hill and it loses power it's most likely a clogged fuel filter not allowing enough extra gas to pass for the additional need. If you're running level at a constant speed and lose power it's more likely the fuel pump is cutting out.

[rgatijnet1]

koda55 wrote:
I would put about 4 cans of seafoam on the gas. Besides the bad fuel filter you could have some gummed up parts in the system.

That's a good idea as there just might be some water in the gas tanks also.

[koda55]

I would put about 4 cans of seafoam on the gas. Besides the bad fuel filter you could have some gummed up parts in the system.

[G_Lewis]

With an older unit, change oil, filter, flush coolent, transmission, etc. Start with a clean slate and then you know.

[turbojimmy]

rgatijnet1 wrote:
Depending on how often the coach was used, there could be some old gas and the crud is just starting to break loose. I would get at least two filters to have a replacement if the new filter plugs up also. You may need to flush the entire fuel system, including the tank, if the coach sat for a long time.

Mine sat for at least 6 years in a tow yard. Like a dope, I didn't change the fuel filter when I first put it on the road. It wasn't too long before it started to show signs of leaning out. Eventually it failed completely along the side of the road.

I replaced the in-line filter with a clear one so I could see what's going on. I also bought a spare. So far that replacement is holding up well with very little crud inside it. I've put a little over 700 miles on it so far without any issue.

To the OP - you may have an electric fuel pump installed on the right frame rail by the fuel fill. A lot of manufacturers did this to supplement the original mechanical pump. This is usually where you'll find an in-line filter as well. That's the one that was bad on mine.

[rgatijnet1]

Depending on how often the coach was used, there could be some old gas and the crud is just starting to break loose. I would get at least two filters to have a replacement if the new filter plugs up also. You may need to flush the entire fuel system, including the tank, if the coach sat for a long time.

[Candikane]

turbojimmy wrote:
When I first got my '84 running I had a similar issue, but it quickly deteriorated into a no-run situation. Fuel filter was bad - I would agree with the previous advice. Start there. There should be an inline filter as well as a filter at the carb inlet.

Thanks! We haven't tracked down a manual yet, so this is really helpful 🙂

[turbojimmy]

When I first got my '84 running I had a similar issue, but it quickly deteriorated into a no-run situation. Fuel filter was bad - I would agree with the previous advice. Start there. There should be an inline filter as well as a filter at the carb inlet.

[Candikane]

Not yet, we just picked her up. That was our first hunch too.

[zman-az]

Easiest thing to do is replace fuel filter, have you done that yet? Also check that all fuel line clamps are tight.