the Wasp

My Feedback: (1)

I'm starting to get annoyed here !!!!!

(MVVS 35cc red head gasser) (this motor has only been run for about 1&3/4 gallons)

so if you remembered my carb has never pulled/pumped fuel as it should,,, so today I took the carb down and had the chain saw shop guy replace the gaskets (he has been working on these Walbro carb's for 10 years, so I'm sure he know's what he's doing),,,

well,,, it still will not pull/pump fuel !!!

1) there is NO leaks in the fuel lines or any other line !!!

2) I get a pulse !!!

3) pulse seems to be strong !!

4)pulse tubing is new !!!

5) no leaks on the pulse line !!!

6) I have a new gaskets to seal the carb to the manifold !!!

""what do I try next ??!!""

Jim

DarZeelon

Jim,


Maybe your carburettor needs to be primed, for all the diaphragms/valves to seal properly and do their job???

If not, it seems to be some kind of plumbing problem, maybe in your tank, or the fuel tubes.
Your engine's problem seems to be quite unique.

Maybe Pé, or David can think of something else?

the Wasp

My Feedback: (1)

it is NOT a plumbing problem, the fuel line work's great !!!!!!!!!!!!!!!!!!

I have even tried it with a new line and a cup of fuel !!!!!!!!


I took the carb back to the shop,

my friend remover the diaphragms and he took a flat jig type gauge and set it on the carb, then took a flat tool much like screw-drive, and he adjusted the height of that flap on the spring (he checked it and adjusted it a couple times), then he took a small hand (air) pump and hooked the hose to the fuel nipple and he pumped, the gauge on the pump went up to 20 pounds, when he pushed on the flap on the spring the air in the pump was realest,,, he now put the carb back together,,,

at home I remounted the carb and it still wont pull fuel !!!

Jim

the Wasp

My Feedback: (1)

I just removed the carb,,, and removed the diaphragms and put a few drops of fuel in the carb and it still will not pull fuel !!!!!!!!!!


Jim

David_Moen

How old is the engine Jim? Did you buy it new? Does it pump fuel when it's in the shop, can the mechanic confirm that it is working properly in his shop?

I have had a few that are reluctant to pump fuel until all the chambers in the carb are full of fuel. The only way to make this happen is to choke the engine and turn the crankshaft so that engine vacum can pull fuel up to the carb.

the Wasp

My Feedback: (1)

he could not confirm the carb was pumping at the shop,,, this motor will b a year old in July,,,

and this carb has never pumped fuel, it always' took me 55 to 60 flips to start this motor, and then I had NO pulling power from it on my take-off's,,, see my posts,,,

http://www.rcuniverse.com/forum/%22%...2246330/tm.htm

http://www.rcuniverse.com/forum/35cc...2268561/tm.htm

http://www.rcuniverse.com/forum/35_g...2399987/tm.htm

I will fill the carb with my fuel pump and let it set for an hour, then see if it will work.

Jim

David_Moen

Why drive yourself nutty? Call your dealer and ask for a new carb!

the Wasp

My Feedback: (1)

I just called Robert at Morris, he remembered me and my plane (that's a first), and he told me to call him tomorrow and he will help me, he had someone in his office so he couldn't talk..

Jim

pe reivers

The Walbro carb sometimes has this problem when it is not primed properly, that is why almost all garden appliances have a priming bulb pump to fill up the carb with gas.

Failing that device, you need to first choke the engine by <COMPLETELY> blocking the carb venturi, so you draw raw fuel into the carb. Once filled up, the carb should pump ok, and react to normal choke procedures.
I do it this way, for the first start of the day:
I close the choke valbe, and then press on it with my thumb to make sure it closes completely, at the same time closing the small hole in the carb. Then I flip the prop te get the fuel well into the carb. I have my engine mounted in the 7.30 position, so any excess fuel drips out of the carb, and not into the engine.

As to your previous posts.
The mechanic tested the hold pressure, then he tapped on the lever to release the pressure. He did not test if the carb would lift the needle all by itself, and at what pressure. He also did not verify the pumping action. The guy did a great job, but stopped halfway through.
I get the feeling that you run the engine with too lean an idle mixture. Just a feeling though. The needle should be open at least 1.5 turn to start with. A lean idle is one thing you do not want to have.

the Wasp

My Feedback: (1)

it was never ran or flown lean (high or low needle) my background in heli's made sure of that !! I know the high needle was not lean because I used a tach, and I know the low needle was/is not lean because if I got that sharp lean exhaust sound I would open it back up to get that rich sound !!

I just tried a larger I.D. pulse hose and I got a stronger pulse but STILL it will not pull fuel, and I just tried completely choking the carb throat and it did not work !!

I called robert and he will not send me a carb unless I send him mine first and then there is no guaranty he will replace it...

Jim

the Wasp

My Feedback: (1)

I even tried priming the carb by pumping fuel in it (by hand pump),,, and it still will not pump !!

Jim

pe reivers

If:
- the valve plate is nice and soft and fitted right (the mechanic checked that did he?),
- and the fuel regulating valve does not stick,
- And the (also soft) regulating membrane can open the regulating needle on fuel demand (right way up, with the metal disk inside)

it should pump if you bump the prop to and fro against compression while closing the choke.
If not, there is a blocked passage or the internal strainer is clogged up.
If all fuel passages in the carb are present, A thoroug cleaning of the carb should cure any blocked condition, and then it should pump. The gas line is fitted to the nipple in close vicinity of the cast cover isn't it?

the Wasp

My Feedback: (1)

well, I have had enough of this crap !!!!!

I took the carb back to the shop and my friend took it apart again (3rd time),,, cleaned it again, blew it out with air and checked the needle/spring flap with the jig gauge again,,, (all gaskets are new)

the best we can do is to get the fuel to pulse back and forth in the fuel line, the fuel will not move threw the fuel line, it just pulses back and forth !!!


Jim

David_Moen

Like I said, call Morris Hobbies and request that they replace the carb. The engines are covered by a 2 year warranty. Unless you like the process of troubleshooting the problem (doesn't sound like it) or are a machoist (your call) there's an easier solution!

meljoyviegas

My Feedback: (22)

Hi Jim, Seems like you have the same problem as I am haveing with my MVVS 2.15 motor. Then engine I have is new and does the exact same thing as yours. I tried about everything in the book to get it to run but sad to say it got the best of me. So if you have any info you would like to share please do. Thanks Hank

meljoyviegas

My Feedback: (22)

I have an MVVS 2.15 gasser and I was going throught the same thing. I tried everything and everything that I thought would resolve the problem. I even replaced the darn carb. But still no improvement. To cut it short I pretty much did everything you did. Heck I even tried changing out the spark plugs to NGKs, champion, and other types of spark plugs that would fit. Non worked. Then I went out and got a brisk spark plug (UR17 to be exact, like the original). And guess what? Problem solve. Hope this helps.

the Wasp

My Feedback: (1)

to bad this post came back on us,, meljoyviegas, in the end it was a defected carb, it would not pull fuel, a new carb fixed the problem instantly,,

it's a wonderful little motor, with a 5 cell battery pack it starts on the 2nd, 3rd or 4th flip, I'm very happy with it..

Jim