Dixon/Honda 670GXV TAF2/Fuel Delivery! Bubbles!!!!

BooVuc

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I have a used Dixon Grizzly 60 circa 2005 with the Honda GXV670 TAF2 motor. I have surging at both Wide open and low RPM's. I took the carb off and cleaned it up, replaced the fuel lines, installed new shutoffs on both tanks and changed out the 3-way splitter. (two tanks on this commercial unit).
I still have the surging and no idle. It cleans up some what by choking it. I noticed on my fuel filter I have bubbles entering the fuel filter from the supply side.
Anyone else see this on their machines?
On my next venture of puttering with this:

1. I'll change the "new" fuel filter out. (Maybe plugged).
2. I'll blow out the bottom outlet nipples on both tanks.
3. I'll drill out the fuel caps on both tanks to assure they are not causing some vacuum though I see the bubbles with the caps off.
4. I'll change out the small line from the filter to the carb.

I have a small gas tank with a shutoff that I could hook up temporarily and see if it runs better from it.

Am I missing anything going forward? There are no screens in these Dixon tanks per the parts lists. The tanks feed from the deep end needless to say that is opposite the fuel cap so I can't look down in to see if there is debris. I ran some string-trimmer line through the outlet nipples and felt no resistance and I got no debris out of the tanks doing a quart flush on both tanks BEFORE installing the shutoffs!
Frustrating!

Thanks in Advance!
 

bertsmobile1

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Bobbles mean that the fuel lines are sucking air.
If the fuel level in the float bowl is low then you get no idle as at idle there is much less "wind" passing over the venturi at a much lower speed so there is less energy available to suck the fuel up.
Sounds like a time for a good carb clean and to double check the clamps on the fuel lines.
Please do not drill the caps all that does is allow for excessive evaporation of the volatiles.

You are following the correct path surging is always fuel related.
A thorough clean of the car, paying particular attention to the float needle.
Use your spare tank to check the float height at cut off.
The top of the float should be square on to the float body.
I suspect yours will be cutting off too early

When you unscrew the main jet . look at the bottom of the emulsion tube.
If it has a slot then it unscrews most of the way out but you need to push it the the last bit I use a rounded off cut down allan key.
If no slot then use a screwdriver through the carb mouth to push the tube down then the allan key if it does not fall right out.


You can start by hooking up your spare tank to the fuel pump and see if the problem goes way, that eliminates everything on the supply side of the pump.
While it is always better to work from the cap vent to the carb because problems up stream create problems downstream, in real life the carb is the root of most of the problems
 

BooVuc

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When I did the lines over, I reused the clamps. I can always go new with them. I'm going to try the auxiliary tank and see what happens. Thanks for the further suggestions. I appreciate the help!
 

BooVuc

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  • / Dixon/Honda 670GXV TAF2/Fuel Delivery! Bubbles!!!!
I took all the old clamps off and used new screw-down clamps. I then changed out the small line from the fuel filter to the carb inlet. (Clear Tygon line). I also changed out the fuel filter again and purged the lines from each tank to the filter inlet to make sure there were no air pockets in the fuel lines. Same issue! Bubbles in the fuel filter inlet. Even at idle or what I could get of an idle. Sometimes it would idle fine but after running it up to full throttle, it wouldn't have enough fuel in the carb to idle when I brought it back down. You could see visible large gaps of no fuel going into the carb.
I had this carb off to do a good cleaning weeks ago but found the previous owner or his dealer or my dealer I got it from stripped out two of the four bowl screws. They are so far gone I couldn't even get a Dremel tool to score a blade cut in them. Couldn't even get an easy out on them.
While I had it off the machine, I sprayed everything I could get to with carb cleaner then set it up-right on the bench and filled it with carb cleaner overnight. Next morning, dumped it out, re-sprayed and used canned air through what was visible. Afterwards, the machine actually idled on startup so I know I got most of it clean with the exception of the main jets and the bowl itself. (2 barrel carb). This machine had NO idle and massive surging before I cleaned the carb as best I could so I still think its in the fuel delivery.
I didn't have anyone to help me with it today to hold onto my little 1/4 gallon tank to see how it ran directly from it and if I saw the bubbles again.
I just don't get where the air is infiltrating those lines. I tried each tank individually and then with both open. I also had the gas caps loose when running.
Maybe when the grass starts to back off with some hot dry weather, I'll pull the carb again and take it to a small engine shop and have them try to get those screws out. But the carb is one thing. The fuel to it is another and I'm completely stumped! It was 95 in the shade when I worked on it today. Maybe tomorrow I'll enlist someone to hold the little tank freeing me up to tinker and watch.
Since this is a TAF2 carb, the cheap China carbs for these do not have the same line hookups. I know this because I bought one and I got no fuel into it. If there is away to make one of them work with this Honda engine, I'm all ears and eyes. Any more suggestions would be much appreciated!
 

BooVuc

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  • / Dixon/Honda 670GXV TAF2/Fuel Delivery! Bubbles!!!!
Hi Guys/Gals,

Well I removed the fuel filter, installed a new one and hooked up my little reserve tank to the machine keeping it level to the carb intake. I fired it up and watched the filter. I still had bubbles but nothing like I had through the OEM system. However, it still used up most of the fuel in the filter housing after running wide open and in turn, would not idle after I lowered the RPM's. Next, I took the tank and raised it higher than the carb by about 2 feet and I got the same results. The filter did not fill with fuel as it should have. The thing idles when first fired up and it will idle fine for awhile before starving after full throttle operating.
I am going to order a new fuel pump for it. Doesn't cost much and I want to remove that from the equation.

PS....I noticed that the first amount of fuel coming out of the lines was tinted red after sitting a few days. Again...all the lines, the splitter and the shutoffs were changed out. I also drained each take and ran IPA then fuel through them before redoing the fuel system. I have some exposed metal somewhere in each tank. There is a metal gas nozzle on each tank's outlet. Otherwise, where is this tinted gasoline coming from? There is no sign of water in the filter. If I drain a few ounces, it clears right up with no particles observed! I may run a strong magnet along the bottom of eac tank and slowly bring it up the sides near the gas cap and see if it raises any iron or iron residue.
I got me a dandy used Dixon! :frown:

Thanks for being patient with me! (So far).
 

BooVuc

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OK.................I replaced the fuel pump and that was 80% of the issues on idling and pulsating RPM's. I did spring for a new carb so all in all here is the low down over a few weeks to get it right:

I emptied and flushed both fuel tanks with acetone then cheap gas before filling with 89 octane pump fuel. I replaced every line and shutoff on both tanks, replaced the T connector, replaced the fuel filter needless to say and changed the air cleaner and still had a lot of air coming into the pump and carb from the clear line installed from the fuel filter. (Small bubbles into the filter, large gaps of air coming out).
I changed out all the small lines with clear Tygon tubing from the filter to the pump and from pump discharge to the carb fuel inlet.
Next, I changed out the fuel pump but left the original carb on and it idled without choking indefinitely for the first time since purchasing it this Spring. (Woo-Hoo). It still however pulsated slightly at WOT so tonight I put the new carb on it and it runs like it should finally.
Now I can get the stripped out bowl screws out of the original carb and get it cleaned up and ready in the event the new carb starts going south. This weekend, it gets AV-100, (Aviation Fuel/No Ethanol), in each tank to lessen further the chance of it repeating these same issues and to see if the tinted red gasoline at the very end of the fuel system goes away. (Fuel in the tanks is not discolored).

Sorry for the long thread but it may help someone else with a twin GXV Honda. Thanks for reading!
 

bertsmobile1

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OK.................I replaced the fuel pump and that was 80% of the issues on idling and pulsating RPM's. I did spring for a new carb so all in all here is the low down over a few weeks to get it right:

I emptied and flushed both fuel tanks with acetone then cheap gas before filling with 89 octane pump fuel. I replaced every line and shutoff on both tanks, replaced the T connector, replaced the fuel filter needless to say and changed the air cleaner and still had a lot of air coming into the pump and carb from the clear line installed from the fuel filter. (Small bubbles into the filter, large gaps of air coming out).
I changed out all the small lines with clear Tygon tubing from the filter to the pump and from pump discharge to the carb fuel inlet.
Next, I changed out the fuel pump but left the original carb on and it idled without choking indefinitely for the first time since purchasing it this Spring. (Woo-Hoo). It still however pulsated slightly at WOT so tonight I put the new carb on it and it runs like it should finally.
Now I can get the stripped out bowl screws out of the original carb and get it cleaned up and ready in the event the new carb starts going south. This weekend, it gets AV-100, (Aviation Fuel/No Ethanol), in each tank to lessen further the chance of it repeating these same issues and to see if the tinted red gasoline at the very end of the fuel system goes away. (Fuel in the tanks is not discolored).

Sorry for the long thread but it may help someone else with a twin GXV Honda. Thanks for reading!

Be careful using avgas as some avgas will dissolve nylon .
Looks like the bubbles were from a punctured diaphragm in the fuel pump.
If you still have the old one break it open and have a look.
The red colour is simply the fuel going stale.
Air is reacting with some of the stuff in there which turns it red or causes they yellow dye to go red.
If you leave some in an open bowl is usually goes red in an hour or so.

Good to hear you got on top of it and even better you did us the cortesey of the final post to close the thread.
 

BooVuc

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I took the old carb apart and have it soaking in Berryman's cleaner overnight. (The main jets came out without a hitch). It looked very clean. Even the bowl was spotless. The left and right barrel needle valves are enclosed in metal from the housing top to prevent them from being fooled with. (Thank you California)! :thumbdown:
Short of using a Dremel cutoff disc which I don't own to cut the metal from the housing, do those metal blade-tipped tops on the needle valves come off with some extreme pulling?
I am guessing that is the issue on the carb and no way to get them out to clean them up! If they don't come off, I really won't know if I got this now "spare carb" clean enough to put back on if the need arises!
Thanks as Always.
 

BooVuc

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Online after a little searching I found that heating them up will pop the adhesive holding the caps so that is what I'll do.
I use Av100 Gasoline in everything I use. Four old Wheelhorses, 4-stroke pushmowers, a Honda and a Kawasaki powered generator, in the mixes for my Echo Blower, Homelite Weedeater, (3) lawnboys and now the Honda powered Dixon Grizzly.
I haven't found any issues in running it in that array of engines over the past three to five years. It would have been in the Dixon from the get-go had my local airport been open to get 10 gallons of it.
Thanks!
 
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