We just returned from a 400 mile round trip to Silver City NM, staying at Burro Mountain Homestead (3rd time). The trip was the first trip since modifying the carburetor filter inlet housing in an effort to finally cure the fuel starvation problems that have plagued this coach ever since I have owned it. I have to say the modifications (http://www.gmcmhphotos.com/photos/g6819-carburetor-fuel-return.html) were 98% successful.

The trip from Tucson to Burro Mountain starts at about 2,500 ft and ends at about 6,600 ft. There are several up and down grades along the route, some fairly steep. I have had 'vapor lock' issues on this route before, but this time, I had not so much as a cough the whole (almost) trip. Up the hills, towing the Tracker, flat out, four barrel open, vacuum gauge reading 2 - 3 inches, temps in the upper 80s t0 lower 90s, were no problem, without even turning on the electric booster pump. The only issue I had was on the last few miles from home which involved accelerating from a red light to 45 mph, up a hill, in 100 degree heat, after driving 15 miles across town on surface streets. Turning on the electric pump cleared things up for the most part.

All in all it was a great trip with only minor issues with the coach. The right outer CV boot blew out and sent grease flying all over the suspension on that side. We discovered a new window leak on the left large window during a downpour. The generator conked out after running the roof air for about half an hour and wouldn't restart. All relative minor problems that are easily fixed. The Silver City area is beautiful, especially the area known as the "Trail of the Mountain Spirits" east and north of tow, Some of you may have seen some pics I posted on Facebook. About 20 degrees cooler up there thyan Tucson too. Highly recommended as a trip destination.

Just did 800 miles into Central Washington and over 3 steep mountain
passes at +90 degrees. I experienced vapor lock for the first time
(other than that slow-speed, street stuff that Carl talks about). 93°,
low on fuel and 4000ft Blewett Pass was the right combination. I'll bet
those last 15 gallons of fuel were damn hot.

Looking at the pictures, Carl, and there's one change I would make.
Running even a short piece of fuel hose on top of the engine like that
has caused problems in the past. There's a reason the fuel line to the
carb is all steel. Keep an sharp eye on that rubber hose. I'll be
doing a solid steel line, I think.

Thanks for the tip.

Kelvin
'73 23' in Eugene, OR

> Carl S. wrote on Sat, 01 August 2015 17:33
>> We just returned from a 400 mile round trip to Silver City NM, staying at Burro Mountain Homestead (3rd time). The trip was the first trip since
>> modifying the carburetor filter inlet housing in an effort to finally cure the fuel starvation problems that have plagued this coach ever since I
>> have owned it. I have to say the modifications (http://www.gmcmhphotos.com/photos/g6819-carburetor-fuel-return.html) were 98% successful.
>>
>> The trip from Tucson to Burro Mountain starts at about 2,500 ft and ends at about 6,600 ft. There are several up and down grades along the route,
>> some fairly steep. I have had 'vapor lock' issues on this route before, but this time, I had not so much as a cough the whole (almost) trip. Up
>> the hills, towing the Tracker, flat out, four barrel open, vacuum gauge reading 2 - 3 inches, temps in the upper 80s t0 lower 90s, were no problem,
>> without even turning on the electric booster pump. The only issue I had was on the last few miles from home which involved accelerating from a red
>> light to 45 mph, up a hill, in 100 degree heat, after driving 15 miles across town on surface streets. Turning on the electric pump cleared things
>> up for the most part.
>>
>> All in all it was a great trip with only minor issues with the coach. The right outer CV boot blew out and sent grease flying all over the
>> suspension on that side. We discovered a new window leak on the left large window during a downpour. The generator conked out after running the
>> roof air for about half an hour and wouldn't restart. All relative minor problems that are easily fixed. The Silver City area is beautiful,
>> especially the area known as the "Trail of the Mountain Spirits" east and north of tow, Some of you may have seen some pics I posted on Facebook.
>> About 20 degrees cooler up there thyan Tucson too. Highly recommended as a trip destination.
> That's enough for me to move forward as well.


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On 8/3/2015 2:19 PM, Carl Stouffer wrote:
> I will keep a close eye on the rubber line at the carburetor. In the past, many vehicles have had rubber fuel lines on top of the engine, maybe not
> from the factory, but lots have run them with no issues. My thinking was that the rubber connection provided a little bit of flexibility. I don't
> know if that is needed or not. A different fitting or two would allow an all steel flair connection just as easily, and I may change that at some
> future point.

The rubber tends to get very hot, very hard and eventually cracks. A
real issue if you haven't blocked the exhaust crossover. My PO told me
about smelling gas and popping the hatch to find pools of fuel being
held in the intake manifold "pockets" because of a split hose. I think
I heard of other GMC fires caused by the same problem.

Again... there's no pressure in that line but the rubber will suffer the
same torture. It may never split, however.

I don't think you'd need any flexibility assuming you secure the steel
line carefully, which it looks like you're already done with the current
setup.

It's probably not an issue. I just tend to think in terms of NEVER
having an issue. :^)

Kelvin
'73 23' in Eugene, OR

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