Honda GX390 not getting fuel...

[dart451]

Hello all, Working on a NorthStar Generator 8000, w/Honda GX390 engine. Engine was sitting for several years, replaced carburetor and customer had it running, using almost a tank of gas until it started having fuel problems. Customer put on a clear fuel filter inline and fuel still not getting through it. I get generator back, I remove tank, flush out thoroughly, replace all fuel lines, still doesn't get fuel through filter. I took off fuel line from filter, fuel poured out of the new fuel line from tank! At first I thought it might be the fuel cap not venting but it still won't flow with fuel cap off tank... I'm posting a couple pics...could it be the cheap fuel filter, perhaps its not big enough?

[Arkie]

Couple hints about genny fuel system:

I cannot tell for sure by looking at your pic's, but usually on Honda's and other small gen's especially with a on top gas tank there is a petcock on the bottom of the tank and on the end of the petcock up inside the tank is a pre-filter screen and also if the petcock is kind that can be taken apart their is a additional finer screen inside the petcock assembly and they will get restricted and the gen will starve for fuel.

Sometimes you can pull the fuel line off at the carb and the fuel line will flow gas good for awhile and then slow down.
Engine will start and run for awhile after it's rested.

You can remove the gas cap and blow low pressure air, about 3 lbs back through the fuel line to the petcock and up into the gas tank and momentarily clear/backflush the screen in an emergency situation, even use your mouth to blow backwards, but this is only temporary because you push the gunk back into the gas tank. The on top gas tanks have a low sump so as to burn the last of the gas in the tank and the low portion at the petcock is also where trash settles.

You will have to drain and remove the tank and give it a good cleaning and the pre-screen filters
AND for a in-line fuel filter for Gravity fed gas systems (no fuel pump) you should be using the Briggs RED 150 micron fuel filter.
The WHITE finer 75 micron fuel filter is to fine for gravity fed fuel and the engine may starve for fuel.

If you find good filters in the petcock and fuel tank you can remove your fuel filter or use the Briggs RED. Do not try the flea bay Clone aftermarket Red filters, they are POS and will eventually leak at their seams. NAPA has the good red ones also.

AND it appears that your fuel filter is the clear plastic type and I've seen engines operate ok and that type filter and show very little visible fuel inside, making one think that fuel flow is a problem.

[dart451]

Thanks a lot for the long reply! I have already taken the tank apart, flushed it as well as I can, there is no gunk in the tank at all plus there are no screen filters. Like I said previously, when I remove the fuel line from the fuel filter, fuel flows through it profusely! So, I will try the Briggs Red filter and see if that will work...

[KE4AVB]

A couple things I see off the bat.

• Fuel filter appears to be installed backwards. So if it is plugged with trash you won't see it.
• Second the filter is a 75 micron which is intend for fuel pump and not gravity fed systems.

Try a fuel line without a filter and see fuel makes to carb with this temporary line.

Arkie the white Briggs filter is 75 micron (intended for fuel pump systems) and not 150 microns (Gravity Fed systems) like the red one.

[dart451]

KE4AVB, the fuel filer has an arrow on it showing the the fuel flow direction so I assumed it was correct. But, I've learned something today, I didn't know there was a difference in fuel filters. Going into town tomorrow...will pick up some red filter at Napa! I would have installed a temp line all the way to the carb but the line that goes to the carb is a 3/16". It goes into one side of the filter, the other side is a 1/4" line.

[Arkie]

Thanks a lot for the long reply! I have already taken the tank apart, flushed it as well as I can, there is no gunk in the tank at all plus there are no screen filters. Like I said previously, when I remove the fuel line from the fuel filter, fuel flows through it profusely! So, I will try the Briggs Red filter and see if that will work...

AND

sometimes you can remove a fuel line from a gravity fed and fuel will flow profusely at first then slow down profusely after awhile.

If you check the flow into for example;e a quart or gallon jug and gas keeps flowing good for at least a quart the issue is elsewhere.

I remember a old model jeep that would intermittently starve for fuel, sometimes would run for days, then quit. New fuel pump, carb/needle/seat, still same. Let it rest for few minutes and it would go again sometimes for days sometimes just few minutes.
Was way back in the mountains (4x4 rough territory) once when it kept stalling and a helper and I removed the hood and air breather and kept the carb primed from pop bottle gas especially when going uphill. Windsheld was off the jeep where he set straddle the engine on the cowling for a prime when needed. Dangerous as heck but we did not have to walk out.

Finally found a BIG full sized post oak leaf drifting around in the gas tank.

[dart451]

I would certainly agree with you if I hadn't done all the work I've done on the tank and all new lines. That's why this is so frustrating...you do everything you think should be done and you're still stuck in the river without a paddle! lol

[Arkie]

I would certainly agree with you if I hadn't done all the work I've done on the tank and all new lines. That's why this is so frustrating...you do everything you think should be done and you're still stuck in the river without a paddle! lol

Right: Patience
You will want to kick yourself after when you find the problem. (how do I know this)

You can easily do as KE4AVB suggests by removing the existing filter and splicing the different size fuel lines easily by getting a barbed hose line splicer while at Napa. The inline type have step barbs that taper from about 1/8 inch to 3/8 inch and you cut off the smaller sizes not needed if desired. Keep the plastic barbed vacuum splicer away from hot things like ex pipe or muffler because they will melt if exposed to high heat.

I keep some splicers around and T's for quick test splicing of different size vacuum lines and can be used for temporary test splicing your different size low pressure gravity feed fuel lines. The tapered splicers don't even need a hose clamp when doing a temporary test where you are watching the splice.

Let us know what you find?

[bgsengine]

Not to mention,dont forget to check the I.D. of the fuel lines to make sure installing the filter isn't catching the inner liner of the line and crimping it closed. Better yet , just replace the fuel lines with new.

[Arkie]

Not to mention,dont forget to check the I.D. of the fuel lines to make sure installing the filter isn't catching the inner liner of the line and crimping it closed. Better yet , just replace the fuel lines with new.

Right: I started to mention such. I've seen a inside liner on fuel lines separate from the exterior and create a flapper type intermittent restriction. (really a pain to find when intermittent restriction)

Like you say, replace the fuel lines when you are having issues similar to what you have and sometimes just cutting or disturbing an old fuel line to install a filter will shed some loose particvles and then it's headed towards the carb after the new filter.