Fuel Milage. Fuel Tanks and FYI: pulling a GMC Motorhome update

[doyle todd]

For all those with the suggestions about pulling a GMC motor home......
Thank You!!!

We got the engine running and drove the coach home. No problems at all 6
hours of running and nothing but smooth sailing!
I now am the proud owner of a 1977 GMC motorhome. It is a transmode but I
am unsure as to who did the conversion.

First, After 350 miles I got around 5 to 6 miles per gallon with the Genset
and 60 to 75 Average MPH on relatively flat land.
How is this? And what kind of mileage do you get?

Second, I could only get 30 or so gallons of gas in the coach and the gauge
only show between a 3/4 and full. On the first fill up I ran out of gas
going up hill show E and still could only get 30 gallons in it. Suggestions
and thoughts????

Again Thanks for all the help with pulling. If we had not gotten the coach
running we were going to pull it to the nearest service facility for repair.

Jack Todd
77 Something...

 

[thom hole]

Each of the fuel tanks holds 25 gallons and each has a vent line that runs
across the top of the tank. I think that one of the vent lines has closed
up either by being squashed between the tank and the coach or has been
clogged through non-use. The Tank with the closed vent line would only
hold 5 gals until the gasoline has gone above the inlet, which is set
fairly low on the side of the tank. Even with this condition, the gauges
should be reading appropriately. If the gauge reading when set to the
truly full tank reads less than full, you may have corrosion on the
electrical terms that run from the sending unit in the tank to the switch
on the dash. Any corrosion will add resistance and foulup the readings.

In any case you are looking at 'dropping the tanks' to get to the vent
lines and the sending gauge connections.

>For all those with the suggestions about pulling a GMC motor home......
>Thank You!!!
>
>We got the engine running and drove the coach home. No problems at all 6
>hours of running and nothing but smooth sailing!
>I now am the proud owner of a 1977 GMC motorhome. It is a transmode but I
>am unsure as to who did the conversion.
>
>First, After 350 miles I got around 5 to 6 miles per gallon with the Genset
>and 60 to 75 Average MPH on relatively flat land.
>How is this? And what kind of mileage do you get?
>
>Second, I could only get 30 or so gallons of gas in the coach and the gauge
>only show between a 3/4 and full. On the first fill up I ran out of gas
>going up hill show E and still could only get 30 gallons in it. Suggestions
>and thoughts????
>
>Again Thanks for all the help with pulling. If we had not gotten the coach
>running we were going to pull it to the nearest service facility for repair.
>
>Jack Todd
>77 Something...
>