My Tractor Forum banner

1 - 20 of 21 Posts

·
Registered
Joined
·
289 Posts
Discussion Starter #1
I run a power washing business utlitizing two different engines on my setup. One 13hp engine for the power washer and one 11hp unit for the generator (way overkill for the generator).

Its a pain to keep filling the fuel tanks ever couple of hours. I have a 12 gallon tank i could mount to the floor, but it would need a fuel pump to push fuel to the engine from the tank. I am concerned that even a low pressure fuel pump might make too much pressure for the carburetors on these engines to handle.

There is no pulse port to use a pulse type fuel pump.

Do I have ANY options for using a large external tank?
 

·
Jack of All Trades
Joined
·
1,337 Posts
My JD 111 had an electric pump and adjustable regulator on it when I bought it. Don't know why the previous owner spent 4x as much $ on that setup instead of replacing the pulse pump! Anyway, after a year or so the regulator started leaking one weekend, and since I didn't have a pulse pump in stock I eliminated the regulator, figuring I would order the correct pump the next week.....never got around to it...that was almost a year ago and the darn thing has kept purring along with no problems. I was surprised that it didn't over pressure and flood the carb. Not saying it will work in your case, but that is the experience I have had. If it were mine, I would try it, but I would never offer that option to a customer, as it would be a potential fire hazard.

What engines/washer/ginny are we talking about here? Could be convertible to a pulse pump.
 

·
Certified Technician
Joined
·
8,420 Posts
No need...

This is a little trick I picked up building Kart racing engines based on Honda GX engines.

This guy sells modified HONDA carb insulators, you just slide off your carb and insulator, slide his insulator on (with a barb fitting on it) and put the carb and air filter back on. Now grab a pair of Cheap Mikuni pulse style pumps, run a length of hose to to the pulse fitting on the pump and the insulator...voila...pulse driven fuel pump, and you can use the same part on both the 340 and 390, and use the same model pump...Just get a 3 way splitter (if you need one, Ive got some) and plum it up..should take maybe 15 minutes to do the whole thing.

http://www.affordablegokarts.com/mm...de=A&Product_Code=HON16211&Category_Code=GPPX
 

·
Registered
Joined
·
289 Posts
Discussion Starter #5
No need...

This is a little trick I picked up building Kart racing engines based on Honda GX engines.

This guy sells modified HONDA carb insulators, you just slide off your carb and insulator, slide his insulator on (with a barb fitting on it) and put the carb and air filter back on. Now grab a pair of Cheap Mikuni pulse style pumps, run a length of hose to to the pulse fitting on the pump and the insulator...voila...pulse driven fuel pump, and you can use the same part on both the 340 and 390, and use the same model pump...Just get a 3 way splitter (if you need one, Ive got some) and plum it up..should take maybe 15 minutes to do the whole thing.

http://www.affordablegokarts.com/mm...de=A&Product_Code=HON16211&Category_Code=GPPX
I LOVE this idea, thank you so much for posting it. I have to ask tho. How does it work? I dont see how there is a "pulse" in the intake manifold. Just suction. Doesn't the line for the fuel pump have to suck and then blow over and over to make the pump diaphragm pump fuel? It seems to me coming from the intake, it would have constant vacuum. The only way I can see it working is if there is a check valve in the pump, and the check valve closes when the vacuum in the pump becomes equal to the vacuum produced in the intake. Then as fuel is used the springs inside the pump push the diaphragm back and allows the check valve to open again, restarting the process.

Is that how it works?
 

·
Certified Technician
Joined
·
8,420 Posts
During operation the intake alternates between atmospheric and lower than atmospheric pressures, only really produces a vacuum at idle, but a vacuum is not needed, just a pulsing change in pressure.

In the pump, it has a diaphragm, one side is dry..this side has a small weak spring on it that pushes the diaphragm away. The pulse is applied to this dry side, it pull the diaphragm against the spring, then when the intake valve closes, the spring pushes the diapragm back out.

On the wet side of the diaphragm, there are 2 ports...one has a reed valve that only lets fuel in, and one that only lets fuel out. SO as the diaphragm is pulled towards the pulse...fuel is pulled in the inlet...and the instant it stops pulling in, the reed closes, and the diaphragm is pushed back in..and fuel is pushed out the outlet port...

At 30 pulses per second @ 3600 rpms..it moves fuel with ease...
 

·
Certified Technician
Joined
·
8,420 Posts
Works the same at all speeds, just at idle there is a strong vacuum, then atmpspheric pressure, then a vacuum, etc...

And even at idle, still good to go.

I can full an empty bowl in 2 pulls with the engine firing on the 3rd and running...
 

·
Registered
Joined
·
289 Posts
Discussion Starter #10
Ordered one pump and one carb spacer with pulse port today. Also a filter and some fuel line. I noticed tho on their fuel pump setup page that it talks like the carb adapter wont work with a stock carb. What do you think? I don't see any reason why it wouldn't work with a stock carburetor....
 

·
Certified Technician
Joined
·
8,420 Posts
Yeah I dont see anything, unless it interferes with the big stock air filter box? The air box is the first thing I remove and discard, but Id still think the pulse fitting would clear it.
 

·
Registered
Joined
·
289 Posts
Discussion Starter #13
OK I called AGK and they said that the carb adapter referenced in the fuel pump setup page was a different adapter built for the Mikuni carbs. He said the one that I ordered will work fine, so I should be all set tomorrow when the parts get here.
 

·
Certified Technician
Joined
·
8,420 Posts
The folks at AGK are awesome, always have been.
 

·
Registered
Joined
·
289 Posts
Discussion Starter #15
My parts didn't come in yesterday like they were supposed to. Grrr!! Now it will be at least Monday before I have them.
 

·
Registered
Joined
·
289 Posts
Discussion Starter #16
Got my parts today. Kinda disappointed to see that the pulse port on the carb insulator is 1/8" and the fuel line, and pulse port on the fuel pump are 1/4". It'll take a good clamp to clamp the line down onto that line. Think I should send it back to AGK? I did buy a 1/4" x 1/8th NPT barbed fitting (1/4 hose, 1/8th pipe threads) that could be used for a pulse port but that requires drilling and tapping in most cases. I could put the pulse port in the valve cover according to their fuel pump setup page but i question how well that would work, especially with the PCV breather tube right there also.
 

·
Certified Technician
Joined
·
8,420 Posts
I used 1/8" line and stretched it over the fitting on the pump, Iwarmed the line with a hair dryer and it slid on.

Ive also drilled and tapped a valve cover and done it that way, as well ad drilled and tapped a block..the latter of which was iffy, oil would get in the hose and it was not good.

Email AGK and see what they suggest.
 

·
Registered
Joined
·
289 Posts
Discussion Starter #18
Stretching the line would work. I'm a little ocd tho so I like everything to match - I thought about taking a really short section of 1/8" hose - the clear stuff used on things like weed eaters and leaf blowers - and using about 1/2" of that 1/8" stuff sort of as a "bushing" on that pulse port (should make it about 1/4") and then slipping the red 1/4" hose over that.
 

·
Certified Technician
Joined
·
8,420 Posts
That'll work too. I used to be OCD on that stuff too, but then I discovered that this stuff doesnt have ot look perfect to work perfectly.
 
1 - 20 of 21 Posts
Top