Fuel starvation

[abarone300]

My FS 120 R after having been stored for the winter, this time (in the past when this happened, I would struggle with it, but finally it would start, not this time) it would not start! Found out; that the muffler was clogged (some bees had gotten inside via the opening) After installing a new muffler the grasscutter would idle fine after brought to temperature, but when I pulled on the accelerator it would choke and shut down; when switching the knob to "choke" it would accelerate wiithout choking and without shutting down; but of course would not run well and not reach maximum speed since it is set on the "choke" position. Can somebody tell me if this is a classic case of fuel starvation and how I can resolve the problem?

ps - no changes have been made to the carburator's settings, not even the idle speed screw! I've tested the cutter without a muffler installed, and no "choking" has been experienced, since it runs and cuts fine, but of course I can't run it without a muffler installed...

 

[StarTech]

Most likely the metering diaphragm in the carburetor has stiffen and needs replacing.

 

[Fish]

Put up the numbers off of the carb. Just richen the mixture screws a tad.

 

[abarone300]

Put up the numbers off of the carb. Just richen the mixture screws gas a tad.

Good morning Fish, thank you for your answer. I've followed Startech's advise and ordered a seal kit (includes a new diaphragm). You think enriching the fuel mixture will resolve the issue, I really need to use the cutter to cut my grass now, can't wait for the kit to arrive and don't feel like taking the carburator apart to replace the seals if I don't have to ( at least for now, i probably will have to replace them later...); because the grass it's over running my place!
Do you think the diaphram has deteriorated to a point that it prevents enough gas to go though? Thanks

 

[Tiger Small Engine]

Good morning Fish, thank you for your answer. I've followed Startech's advise and ordered a seal kit (includes a new diaphragm). You think enriching the fuel mixture will resolve the issue, I really need to use the cutter to cut my grass now, can't wait for the kit to arrive and don't feel like taking the carburator apart to replace the seals if I don't have to ( at least for now, i probably will have to replace them later...); because the grass it's over running my place!
Do you think the diaphram has deteriorated to a point that it prevents enough gas to go though? Thanks

The only way to know for sure, is to adjust carburetor and see if that helps. If not, step two is to remove carburetor, clean, replace metering diaphragm, and install carburetor. Make sure fuel is no more than 30-60 days old.

 

[abarone300]

OK, I started making the adjustment. Before I realized that the screws can only be turned 3/4 of a full turn, and I ended up over adjusting them! My "tad" wasn't quite your "tad".
Now I can't even start the thing now; because Fuel and Air are way out of adjustment (I suppose they need to be in sink too, and I suppose the engine temperature has to be considered). What is a good starting point, a rough screw setting before fine tuning the two screws, so I can at least start it?
The markings I think are in German: "LA" for idle screw (it's the only screw I'm sure of) and "H" and "L" ; I suppose these two screws are FUEL and AIR? In the mean time I'm going to consult the manual, maybe it has the English translation. Thanks

PS - before I over adjusted the screws, I got it to run pretty good (it was revving ok, except for a small bugging (that's when I exaggerated and messed up)

 

[kbowley]

Take the carb off and get the numbers off it to order the correct kit or take the carb to a dealer and have them install the new carb kit. You may have damaged the adjustment screws. Initial adjustment is 1 1/2 turns out after lightly snugging them up. Regarding the letters beside the adjustment screws, H is high-speed, and L is the low-speed adjustment.

 

[abarone300]

Thanks kbowley, I had it all wrong then:"H" for high speed and "L" for low speed! Is this how all mixture screw work on all carburators; even car's? As far as I know the regulating screws are not damaged, I was veri careful not to overtight them and. And I can only turn the screws 3/4 of a full turn (about 270°)

 

[Fish]

The "L" is the low speed mixture screw, and turning them to the left richens it up. The "H' is the one farthest from the engine, and it richens the same way. There are usually limiters that you cannot richen them and further without removing the limiter caps. So turning them both left to the stop will likely get you back to where you were.

 

[Fish]

I tried uploading the manual but it is too large.
P.M. me if you want me to e-mail it to you.