Muffler ?

[amansfield1104]

Thanks for the comments. I read all the comments again as I finally finished another project so I can get back on the RV.

Part of my problem I assume is the muffler I have installed. I have one muffler that is slightly low and goes across the the bottom. My trip last Nov. we found the back of the RV was warmer than the rest of the RV.

I have never been able to keep the Generator running when driving. After about an hour on the road it quits. When I park the generator will not run for a while. Once everything cools off the generator runs fine. My assumption is the fuel has gotten to warm. I’ve replaced the fuel pump and filter set up on the generator and that did not change anything. I can go out start the generator and it will run for hours with no problem.

I plan to make several trips with the RV do not want to have to use the interstates so that I do not have to go thru a town. It is generally only in town stop and go traffic that I vapor lock or when I stop for gas. Once on the road and good airflow under the RV the vapor lock goes away.

I will change to electric fuel pumps. One pump from each tank. It has been 10 years since I replaced the fuel line so I’ll change the fuel lines and use a T with check valves as Ken suggested. I’ll add installation around the fuel lines and paint the bottom of the tank with some sort of paint that also will insulate the tank some. Oh yea I will wrap the headers and the muffler with insulation.

What muffler should I use.

Art

>
> If you have old hose on the input of the pumps it can collapse under vacuum and shut off the flow. Higher vacuum causes fuel fumes, which only work in
> the intake manifold. Those pumps won't pump fumes fast enough. Haven't checked my fuel pressure at the carb when it happens, but there could be
> pressure with no liquid fuel. If the mech pump gets air it should still prime itself if fuel is available to it. I have power fall-off problem like
> vapor lock and I'm sure old hose is collapsing, unless it's plugged pickup screens. Either way, gotta drop the tanks to figure it out...already did
> everything else except refrigerate the ignition amplifier.
> --
> Terry Kelpien
>
> ASE Master Technician
>
> 73 Glacier 260
>
> Smithfield, Va.
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

 

[jim miller]

> I have never been able to keep the Generator running when driving. After about an hour on the road it quits. When I park the generator will not run for a while. Once everything cools off the generator runs fine.

The next step in troubleshooting this problem is to drop the bowl off the Onan’s carburetor AFTER it has quit while you are on the road. If the bowl is dry then you have a fuel starvation problem and can proceed down that route - OTOH if there is a full inventory of fuel in the bowl then you may have a heat-related ignition problem.

You don’t have an email signature that tells us what kind of coach you have so it is difficult to diagnose further. GM outfitted coaches have a separate dip tube in the main tank to feed the Onan, other non-GM outfitted coaches such as the Royale have a tee in the engine fuel line that serves the genset. Onan cautions against this latter configuration in their literature and they state that it can cause fuel starvation.

—Jim

Jim Miller
1977 Eleganza
1977 Royale
Hamilton, OH

 

[Ken B]

The only time that I had Onan vapor lock was when the outside temperature exceeded 100 degrees. I made the mistake of filling up with 42 gallons at a
"Top Tier" (10% craponol) gas. I spent the day driving 30 to 50 miles and then hiding out in the shade for a while. Same thing happened 2 days later
when the temp exceeded 100. It was a bad week for on the few days that we traveled. I finally got a 5 gallon gas can strapped it to the back bumper
and ran a hose to the Onan fuel pump. I got around 5 hours per fill up but only used it during the heat of the day.

My more permanent solution, after I got home, was to cover the fuel line inside the Onan cabinet and the fuel pump with fire sleeve and aluminum
reflective tape. I assumed those were the hottest areas when the Onan was running and most likely places to boil the gasoline. I have never had an
Onan vapor lock problem since then.

Where you buy and what fuel (not brand) you buy does make difference. Summer mix fuel kicks in on May 1 and June 1. Here is the EPA listings by
county of the RVP required to be sold at retail for on road use. A lower number is better in the listings. Keep in mind if you buy 10% crapnol
diluted fuel, add 1.0 to the number read in the table.

If you read the table closely you will find some strange anomalies. Things like only Elpaso, Texas but nothing in the rest of the state, or parts of
Missouri and all of Michigan.

https://www.epa.gov/gasoline-standards/gasoline-reid-vapor-pressure

Reformulated Gas requirements in EPA non-attainment areas:
https://www.epa.gov/gasoline-standards/reformulated-gasoline

We have one guy at my airport buying and using 100 octane AV gas at $4.00+ per gallon for his generator in an SOB during the summer. I offered to
help him "heat proof" his generator. He refused and said he had money to burn so he will burn it in his generator. He already installed an aux tank
for the generator to use in the summer. AV gas has a RVP of 7.0 year round.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana

 

[amansfield1104]

I have a 76 26’ Eleganza. Yes! It could ignition. I changed the condenser and the coil and it does the same thing. What makes me thing it is a gas temperature problem is how warm the back of the RV was when it was 35 outside. It was actually warmed in the back than up front with the heater on. I had the exhausted checked for leaks last summer as none were found. How can the back be that warm? My assumption is the cross muffler that has both exhausted going into the muffler is heating the back end. SO they will be change in the next few weeks. I looking for a good exhaust shop that can do an RV as mine has closed and the building is no longer there.

Art

>

>
>> I have never been able to keep the Generator running when driving. After about an hour on the road it quits. When I park the generator will not run for a while. Once everything cools off the generator runs fine.
>
> The next step in troubleshooting this problem is to drop the bowl off the Onan’s carburetor AFTER it has quit while you are on the road. If the bowl is dry then you have a fuel starvation problem and can proceed down that route - OTOH if there is a full inventory of fuel in the bowl then you may have a heat-related ignition problem.
>
> You don’t have an email signature that tells us what kind of coach you have so it is difficult to diagnose further. GM outfitted coaches have a separate dip tube in the main tank to feed the Onan, other non-GM outfitted coaches such as the Royale have a tee in the engine fuel line that serves the genset. Onan cautions against this latter configuration in their literature and they state that it can cause fuel starvation.
>
> —Jim
>
> Jim Miller
> 1977 Eleganza
> 1977 Royale
> Hamilton, OH
>
>
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

 

[jim kanomata1]

You might want to replace the oil pressure sender with a lower one as the
oil gets hit , pressure drops and shots the unit off.

On Sun, Mar 24, 2019 at 8:00 PM amansfield1104--- via Gmclist <

> I have a 76 26’ Eleganza. Yes! It could ignition. I changed the
> condenser and the coil and it does the same thing. What makes me thing it
> is a gas temperature problem is how warm the back of the RV was when it was
> 35 outside. It was actually warmed in the back than up front with the
> heater on. I had the exhausted checked for leaks last summer as none were
> found. How can the back be that warm? My assumption is the cross muffler
> that has both exhausted going into the muffler is heating the back end. SO
> they will be change in the next few weeks. I looking for a good exhaust
> shop that can do an RV as mine has closed and the building is no longer
> there.
>
> Art
> > On Mar 23, 2019, at 8:40 PM, Jim Miller via Gmclist <

> >
> > On Mar 23, 2019, at 8:16 PM, amansfield1104--- via Gmclist <

> >
> >> I have never been able to keep the Generator running when driving.
> After about an hour on the road it quits. When I park the generator will
> not run for a while. Once everything cools off the generator runs fine.
> >
> > The next step in troubleshooting this problem is to drop the bowl off
> the Onan’s carburetor AFTER it has quit while you are on the road. If the
> bowl is dry then you have a fuel starvation problem and can proceed down
> that route - OTOH if there is a full inventory of fuel in the bowl then you
> may have a heat-related ignition problem.
> >
> > You don’t have an email signature that tells us what kind of coach you
> have so it is difficult to diagnose further. GM outfitted coaches have a
> separate dip tube in the main tank to feed the Onan, other non-GM outfitted
> coaches such as the Royale have a tee in the engine fuel line that serves
> the genset. Onan cautions against this latter configuration in their
> literature and they state that it can cause fuel starvation.
> >
> > —Jim
> >
> > Jim Miller
> > 1977 Eleganza
> > 1977 Royale
> > Hamilton, OH
> >
> >
> >
> >
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Jim Kanomata
Applied/GMC, Newark,CA
jimk
http://www.appliedgmc.com
1-800-752-7502

 

[amansfield1104]

Thanks good read. I will add the insulation to the fuel line when I place it under the generator. I will add the tape never thought of that. Will rap the headers and mufflers before they are installed. My concern is that will add a lot more heat to the 3” pipe.

These RV can be a problem figuring out what is what. I use to have over heating problem with the 455. I changed radiator which helped but did not fix the problem. I changed the carb set up and richened the mixture and no more over heating problems even when 95F and pulling hills. I guess not having a stock cam was the problem. To my surprise the gas milage was a little better and not worst. I have no idea that my EV has the problem carb on it. Boy did it pull better. Now if I can figure out the generator life will be much better.

Art
76 26' Eleganza

>
> The only time that I had Onan vapor lock was when the outside temperature exceeded 100 degrees. I made the mistake of filling up with 42 gallons at a
> "Top Tier" (10% craponol) gas. I spent the day driving 30 to 50 miles and then hiding out in the shade for a while. Same thing happened 2 days later
> when the temp exceeded 100. It was a bad week for on the few days that we traveled. I finally got a 5 gallon gas can strapped it to the back bumper
> and ran a hose to the Onan fuel pump. I got around 5 hours per fill up but only used it during the heat of the day.
>
> My more permanent solution, after I got home, was to cover the fuel line inside the Onan cabinet and the fuel pump with fire sleeve and aluminum
> reflective tape. I assumed those were the hottest areas when the Onan was running and most likely places to boil the gasoline. I have never had an
> Onan vapor lock problem since then.
>
> Where you buy and what fuel (not brand) you buy does make difference. Summer mix fuel kicks in on May 1 and June 1. Here is the EPA listings by
> county of the RVP required to be sold at retail for on road use. A lower number is better in the listings. Keep in mind if you buy 10% crapnol
> diluted fuel, add 1.0 to the number read in the table.
>
> If you read the table closely you will find some strange anomalies. Things like only Elpaso, Texas but nothing in the rest of the state, or parts of
> Missouri and all of Michigan.
>
> https://www.epa.gov/gasoline-standards/gasoline-reid-vapor-pressure
>
> Reformulated Gas requirements in EPA non-attainment areas:
> https://www.epa.gov/gasoline-standards/reformulated-gasoline
>
> We have one guy at my airport buying and using 100 octane AV gas at $4.00+ per gallon for his generator in an SOB during the summer. I offered to
> help him "heat proof" his generator. He refused and said he had money to burn so he will burn it in his generator. He already installed an aux tank
> for the generator to use in the summer. AV gas has a RVP of 7.0 year round.
> --
> Ken Burton - N9KB
> 76 Palm Beach
> Hebron, Indiana
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

 

[amansfield1104]

Thanks Jim I wonder about that.

Art

>
> You might want to replace the oil pressure sender with a lower one as the
> oil gets hit , pressure drops and shots the unit off.
>
>
> On Sun, Mar 24, 2019 at 8:00 PM amansfield1104--- via Gmclist <

>
>> I have a 76 26’ Eleganza. Yes! It could ignition. I changed the
>> condenser and the coil and it does the same thing. What makes me thing it
>> is a gas temperature problem is how warm the back of the RV was when it was
>> 35 outside. It was actually warmed in the back than up front with the
>> heater on. I had the exhausted checked for leaks last summer as none were
>> found. How can the back be that warm? My assumption is the cross muffler
>> that has both exhausted going into the muffler is heating the back end. SO
>> they will be change in the next few weeks. I looking for a good exhaust
>> shop that can do an RV as mine has closed and the building is no longer
>> there.
>>
>> Art
>>> On Mar 23, 2019, at 8:40 PM, Jim Miller via Gmclist <

>>>
>>> On Mar 23, 2019, at 8:16 PM, amansfield1104--- via Gmclist <

>>>
>>>> I have never been able to keep the Generator running when driving.
>> After about an hour on the road it quits. When I park the generator will
>> not run for a while. Once everything cools off the generator runs fine.
>>>
>>> The next step in troubleshooting this problem is to drop the bowl off
>> the Onan’s carburetor AFTER it has quit while you are on the road. If the
>> bowl is dry then you have a fuel starvation problem and can proceed down
>> that route - OTOH if there is a full inventory of fuel in the bowl then you
>> may have a heat-related ignition problem.
>>>
>>> You don’t have an email signature that tells us what kind of coach you
>> have so it is difficult to diagnose further. GM outfitted coaches have a
>> separate dip tube in the main tank to feed the Onan, other non-GM outfitted
>> coaches such as the Royale have a tee in the engine fuel line that serves
>> the genset. Onan cautions against this latter configuration in their
>> literature and they state that it can cause fuel starvation.
>>>
>>> —Jim
>>>
>>> Jim Miller
>>> 1977 Eleganza
>>> 1977 Royale
>>> Hamilton, OH
>>>
>>>
>>>
>>>
>>> _______________________________________________
>>> GMCnet mailing list
>>> Unsubscribe or Change List Options:
>>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
> --
> Jim Kanomata
> Applied/GMC, Newark,CA
> jimk
> http://www.appliedgmc.com
> 1-800-752-7502
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org