tanaka tc-47 not staying tuned

[keatonx]

If it starts to sound a lot smoother and you need to ease on the gas really carefully to rev it up, it's too lean. It also might "gallop" slightly (best way i can describe it).

If the engine sounds like it's stalling from simply running too slow to stay going, and the sound of the individual power strokes is really distinct, you're probably running rich or you're idle is too slow. If I were you I'd turn in the idle speed screw a full turn or something (so it idles really fast) until you get it running right.

You tuned it when it was fully warmed up, right? Because that's what matters, the whole purpose of the choke is to temporarily change the a/f ratio for when the engine's cold.

If you need to leave the choke on all the time tho, then obviously you're too lean.

I have a feeling you're idle speed is set too slow, and you're naturally trying to make it idle faster by making it run excessively lean. Which causes it to bog out and die every once and a while because it's right on the edge of being too lean to run (very fine line, it'll be like falling off a cliff).

 

[keatonx]

But man, 1/2 turn is a pretty big range, assuming the engine was always fully warmed up when it seemed to want a different position.

 

[HeadSmess]

ok.

now, firstly, is the carb the same as original, or another breed? they do have internal jets, sized to certain engines temperaments, besides having different chokes and throttles and all these other configurations. while you may have two seemingly identical carbs, they can tune differently. anyway.

no sealant is good. have you checked the pump hole is clear? that the gasket/holes in the manifold line up correctly and will transfer crankcase pressure through that tiny little hole in the face of the carb next to the main bore? if it cant pump, it can run sometimes but will be really erratic.

some versions have external pump lines...

if the bores bigger than stock, give up.

back to the first post. get the original carb and strip it. clean it. reinstall it. petrol and compressed air.

you asked how to tune them. here is how.

screw both needles in. all three actually. idle as well.

back them all off 2.5 turns.

helps to hang the thing from a rope if its attached to a bike for this...

start it, let it warm up. it should be buzzing its brains off. let it.

hold full throttle, adjust the hi until it peaks. usually by screwing in.

then back off 1/8 turn.

next, let it idle now. it should be idling fairly fast. clutch will be engaged, etc.

adjust the lo until it peaks. back off a 1/4 turn.

adjust the idle screw so its a bit lower and clutch has disengaged.

blip the throttle. if it coughs, screw lo out a touch. otherwise, screw in until it coughs then back off...

when riding, the hi will determine if it revs out to the top end, so you may have to tweak that a little bit.


the lo determines how it accelerates.

idle screw sets how slow it goes.

but generally, when working, these are meant to be one shot, self adjusting and basically foolproof.

just take some understanding.


oh. and try the odd plug chop

 

[locksmith]

You guys won't believe this!!

First, thanks again to everyone who replied. you guys won't believe this..

I took this to a mechanic before I put the new carb on it, who redid the fuel system to try to fix it.. he took out the return fuel line and gromet and left a hole in the tank...

i could only fill the tank a 1/3 full before gas would leak, so a couple weeks ago, i ordered a return grommet and a tube for the return line. he put an aftermarket primer on, which was ugly so I ordered a new primer assembly to put on it as well.

this morning i put everything on and noticed when the motor started, it sounded much deeper, fuller and healthier. it didn't stall and didn't sound like it wanted to...

it turns out, the primer the guy put through the fuel line was starving it from fuel, which is like drinking from a coffee straw.

look at the diagram, and you'll see that the primer line and return line are on separate "chains" or "systems" and that the main fuel should go DIRECTLY from the gas tank to the fuel intake. so the primer in between was an impediment to the fuel supply.

so no wonder i was having problems... i'd stop along side the road to tune it like a ****, and the whole time, it was the fuel system. on a side note, i am glad i'm going to mechanic school this summer, bcos if you want it done right, do it yourself

here is the parts site! i recommend them, they're cheap and oem parts

http://www.toolpartspro.com/

 

[HeadSmess]

ok.
but generally, when working, these are meant to be one shot, self adjusting and basically foolproof.

just take some understanding.

this is one of those examples of why...i service my own equipment, and service other peoples. there is nothing funnier than fixing something in five minutes a "really good" mechanic couldnt fix in two days...

but yes, it takes some patience. a little bit of thinking. some common sense.

the number of times ive cleaned out carbs because some monkey has gotten the hoses around the wrong way. great when theres only one, but people just dont seem to think, (or care?) when theres two or three. just have to experiment. squeeze the bulb, which way does the fuel or air squirt out? which hose has the filter on the end? how does air get in to replace the fuel thats being used?

yarda yarda.

glad you fixed it yourself.

what do they say? if you want it done properly...


and now...you didnt say what carb you have now, but without that primer...oh yeah now you should see what i was on about...either somethings wrong or somethings wrong when a walbro plays up

 

[locksmith]

this is one of those examples of why...i service my own equipment, and service other peoples. there is nothing funnier than fixing something in five minutes a "really good" mechanic couldnt fix in two days...

but yes, it takes some patience. a little bit of thinking. some common sense.

the number of times ive cleaned out carbs because some monkey has gotten the hoses around the wrong way. great when theres only one, but people just dont seem to think, (or care?) when theres two or three. just have to experiment. squeeze the bulb, which way does the fuel or air squirt out? which hose has the filter on the end? how does air get in to replace the fuel thats being used?

yarda yarda.

glad you fixed it yourself.

what do they say? if you want it done properly...


and now...you didnt say what carb you have now, but without that primer...oh yeah now you should see what i was on about...either somethings wrong or somethings wrong when a walbro plays up

Oh sorry, it's a walbro hda 97


http://wem.walbro.com/walbro/produc...97-1&GroupName=Brush Cutter&FamilyName=TANAKA

Here are pics of the first one that didn't work, cause of a bent piece that was attached to the choke lever. It was getting too much air cause the plate was bent. Didn't figure that out till I compared it to the new one lol

http://www.motoredbikes.com/showthread.php?41633-47cc-Tanaka-stalls/page2

This has been a huge learning experience for me, so thanks to everyone