3w75
 

My 3w75 is hard to choke. Seems like I need to turn the prop many many times before it will prime the engine. Any suggestions on what may be the cause or what I need to check.

RE: 3w75
 

There may be a leak between the carburetor and the engine mix intake. Make sure the carb bolts are tight.

The other possibility is that various passages inside the carburetor are somewhat blocked. The best fix for it is to get a can of carb cleaning fluid from Auto shop (about 1 gallon), and submerge the carb in it for a couple of hours, and take it out and air-blow the cleaning fluid out. You need to take out the diaphragms, and the needle valve first though before the cleaning and assemble them back. It happen to my DA50 and the the cleaning process fixed it. I fix the carb of my lawn mower the same way.

RE: 3w75
 

Thanks for the reply and I will try your suggestions.

RE: 3w75
 

When I bought my 3W75 from my friend he said it takes 17 flips to choke then 7 to start. I took off the choke plate and closed the hole in it with soldier. now it Chokes in 3~4 flips, starts in 2~3 flips.

RE: 3w75
 

Do you have any pics of what you did. Not sure what hole you are talking about. Mine takes about 20 flips to choke and 10 to start

RE: 3w75
 

That's normal until you do the fix. I don't have any pictures, but I'll see if I can take some today.

RE: 3w75
 

soarrich, thanks a lot and I appreciate your effort to get some pics. Look forward to getting them.

Ken

RE: 3w75
 

Last time I had it out it was hard starting, now I know why. The aluminum tape I used is gone. I stopped using the tape a couple of months ago when I found how easy it easy to soldier the hole closed. I decided to fix the choke plate using soldier this time, it turns out it's much easier to soldier a hole closed than it is to soldier the edge of a choke plate. Here's what works:
Hold the plate with pliers and soldier the choke plate with it laying on something that soldier won't stick to. I used an aluminum plate held in a vice, this lets the soldier flow on both sides of the choke plate. After the soldier is cooled file the soldier off, then use the file to refinish the choke plate into a round disc. I made the mistake of hammering the plate to flatten the soldier at first, this stretched the brass plate out of round, so don't hammer it. Even though the edge soldiering is much harder to do than soldiering a hole it still only takes 15 minutes to do, a hole takes about 30 seconds, so it's easy.

RE: 3w75
 

soarrich, thanks a lot for the information and the pics. Now I understand what hole you are talking about. I was about to solder the wrong one. What you have done makes a lot of sense and I will be fixing mine tomorrow. The pics are worth a thousand words. Does the plate come out by removing the one screw? Thanks again, Ken

RE: 3w75
 

Yes. After you soldier it you have to file it back to the same thickness, unlike the Walbro carbs where the plate sits on the shaft, this plate goes through a slit in the shaft, then held in place with the screw.

Let me know how you like it's starting after you soldier it, my friend that sold me the engine nearly fell over when it started so easy.[sm=thumbup.gif][sm=thumbup.gif]

RE: 3w75
 

I will make the mod. tomorrow and let you know how it starts. Looking forward to getting it done to see if it helps. Thanks again,

RE: 3w75
 

Rich,

Here is the results of your suggestions. I haven't tried it yet, but will tomorrow or thursday. I will let you know how it works. Thanks again, Ken

RE: 3w75
 

Please be sure you restake the screw you removed , engines do not like those little screws inside. Don't ask me how I know this. lol

RE: 3w75
 

That would not be a good thing. I did use lock tite to make sure it doesn't come off. I know this will help with the starting.

RE: 3w75
 

Nice job soldiering.

RE: 3w75
 

Thanks,,,,Like you said, it took about 15 minutes to do. Hardest part was the filing to get the solder smooth so it would fit back into the slot.

RE: 3w75
 

Started my 3w75 this morning for the first time after the carb mod. I turned the prop 7 times to prime the engine, turned on the ing. and tried to start. The engine was flooded, so I opened the choke and the engine started on about the 5 flip. It sure works a lot better than before the carb mod. Now all I need to do is determine how many turns it takes to prime the engine and then turn on the ing. to start. I am guessing about 3 flips but will pull the cowl and watch the fuel line to the carb. Thanks again Rich for the carb mod.

RE: 3w75
 

Choke it with the ignition on. It will cough, but not run, take the choke off, it'll start about the thrid flip.

RE: 3w75
 

I'll do that when I go out to the site on Saturday. Sure is a lot eaiser to start.

RE: 3w75
 

Ok guys,,,,,my 3w 75 started on the 5 flip....What a difference the carb mod. makes. Before the fix, at least 20 flips to start. Now 5 and I think it will start in 3 flips. Will be going out Tuesday and will try it again.

thanks to Rich