OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Trimmers and Brushcutters Two Stroke Trimmers & Brushcutters Tanaka TBC23R Starting Procedure

Evening all

Had a go at a Tanaka I picked up a couple years ago. The initial problem was a broken throttle cable. When I got it, it would run but wouldn't rev fully. I got it started with a shot of fuel down the carby.

My query is the actual procedure to start the thing.

It is the same motor and carby in this thread https://www.outdoorking-forum.com.au/forum/ubbthreads.php/topics/49823/re-tanaka-tbc-233.html#Post49823


There is a primer, choke and a knob. The knob appears to block the main jet when pushed up. What I can't work out is the correct way to start it. I am guessing you push the knob up to seal the main jet, pump primer to fill the little float bowl, then pull the knob down to allow fuel up the main jet.


The other issue is the knob leaks - more profusely after I cleaned the carby. I Can't work out how the knob comes off the shaft to remove the shaft and put in o rings.

Anyone worked on one of these before?

Thanks

Hi Tyler,

Have a look at this diagrahm and you will see item 22 which you will need to remove in order to get to the check valve and replace the 'O" ring to stop the leaking.

This isthe link: https://www.outdoorking-forum.com.au/forum/ubbthreads.php/topics/5408/tanaka-brushcutters.html#Post5408

It has been a long time since I have worked on one but I think that the knob might be threaded.

From memory to shut the fuel off you need to push it up and the run position is down.

Many thanks Bruce

I will have a look tomorrow. Must be threaded as it won't easily pull off.

Just an update

Running again.

The knob is a push fit. It is a pretty flexible plastic so you just wriggle back and forth and it pops off.

The o ring was hard so set about finding a replacement. Its a tiny bit bigger but victa fuel tap/ g3 main jet oring GA spares PTC807 fits and works as intended.

For anyone in the future struggling to start one of these, I have been trying different starting procedures. The best one currently is:

Push carby knob up (block main jet)
Prime 5x
Pull knob down
Prime 2x (squirt a bit of fuel in)
Choke on
Throttle a bit off idle

Pull cord and it fires first or second go and dies

Choke half and prime 2x more

then it will start and run mostly fine at half choke for a minute at idle.

Don't know if its the old diaphragm in the pump but it doesn't like being tilted at idle. Can tilt fine at throttle though. Must be fuel flow issue. Will change the tank filter and see how it goes

More problems. Adjusted the mixture and then would idle but not rev well. Then colossally backfired, snapping the starter rope. Then I noticed the phillips heads are stripped on 2 of the 3 pull start screw heads.

Those came out reasonably easily, new cord in, mixture put back where it was and still no good. Thought there should have been a washer to hold the power needle correctly.

Grovelled around on the floor and found it!

Upon reassembly it still ran poor. Pulled the exhaust off - clean port but muffler clogged with carbon severely.

Scrapped all that out and checked. Now sounds better but still won't run right (backfiring)

Working theory was a sheared flywheel key from the massive backfire that snapped the cord.

Flywheel nut is regular thread for any future reader. Got the flywheel off taper and found a perfect key!

I was about ready to pull my hair out when I notice a points case. I thought I saw these had EI but was wrong



Any ideas on the points gap?


Currently 4 thou but am guessing 14 thou or there about would work

You must be keen as mustard on these machines to be that determined Tyler. Just the thought of tinkering with small motors does my head in!
Japanese made beautiful equipment in the 1970s so I can well believe it's worth the effort to get running right.

MF, I have a few vintage trimmers and they are often great machines built properly. But it does give you a laugh how they built some systems. This one has the fuel pump sandwiched between the tank and engine, driven off the crankcase vacuum.

Feeds up to a carby with a bowl with about a 2ml volume which overflows back through another pipe back to the tank. Then there is a third hose running to no where which is a backup overflow I guess.

Is a nice smooth motor when running.

If its the crank seals causing the issue then its a problem.

I am hoping setting the points will sort it. The way it was running it misses/backfires at medium rpm and hits a brick wall at about 5000 rpm.

Working theory is the points being so closed is partly doing the timing but also not able to 'keep up'. ie they can handle 2200rpm idle but either bounce or break down over it.

This explains the strange behaviour of smoke out the exhaust.

It has smoke, then clean for 3 seconds as it dies then backfire and plume of smoke then clean and so on. Plug says very rich. My theory is it fires every few revolutions hence tonnes of fuel in there to burn with tonnes of smoke.

When there was fuel delivery issues it wasn't as bad but now sorted out it is flooding itself between sparks.

By the way MF, the next things in the pile are a pair of 80s stihl trimmers FS51 I believe (one FS51 AVE anti vibe) and one of the first Ryobis from the early 80s (RGH600)

Actually come to think of it I have another RGH600 in the shed to do, and a 90s Mac Cat and others

First Ryobis with Ryan engine? I remember our neighbour in 1987 got a line trimmer with a green engine cover. They were the first household I ever knew to get one. I think it was a Ryobi and it wasn't quite the same as the Lawn Hornet that proliferated the next year in the department stores.
I saw a green Ryobi later on that looked older/different to the common ones and noticed it had an orange choke knob instead of black and a different shape fairing. That may have been the one our neighbours got. Having a line trimmer back in 87 was quite fancy to me and they certainly were in an exclusive group then. Now it's a standard item in every household like a mower.

When we moved in 1988 our new neighbour had professionals come and mow and I remember hearing the Stihl trimmer make a distinct melodic hum from the spinning line end in unison with the motor. I always enjoyed that powerful sound it made.
That was also the year I got my first use of one when a girl from a couple of doors down the street who used to come over to see our cats, got her dad to loan me his McCulloch straight shaft after I said I wished I had a whipper snipper to do the edges. It was a really good one and had a throttle lever instead of a trigger, which I didn't like at the time but now would rather have it that way to be honest.

MF, it is a 17cc motor same as an 80s mcculloch. Not sure if its a ryan motor but same configuration with orange choke knob at back

This is what its like https://www.gumtree.com.au/s-ad/wan...per-ryobi-vintage-suit-repair/1261131990

Update on the Tanaka:

Tested condensor found fine.

Filed points - desperately needed doing. Re oiled felt lubricator and set gap at 14 thou.

All back together and still doing the same thing.

Then I took my own advice and put back in an old champion j19lm instead of the new cj8 that was in there.

The plug was the main problem!

Then the fuel pump died. Turned out the original fuel filter didn't have a 1 way valve like I thought, it was degraded internally and clogged the pump.

Cleaned that out and took it for a 15 minute run and didn't miss a beat

Excellent stuff Tyler!!
Very happy to hear you overcame.

That Ryobi looks more fancy and better quality looking with the orange knob and trigger. I also like the labels. It looks a more premium package than their later stuff.
Honestly, through their lengthy Ryan based engine period, they got worse and worse, not better, particularly that awful easy start engine.
The first 31cc green ones from the late 1980s that sold up a storm sounded better then the white then grey body series that followed.
I find it hard to believe that engine is only 17cc! It looks outwardly the same size as the 31cc which is practically double the capacity.

MF, the motor is noticeably smaller when you hold it and has a complete different tone. the trigger is a weak point and parts no longer made.

I have had one running but behaved oddly and have to figure out the head.

The stihl FS51 is in poor condition carby wise - full of gunk and stinks!

A friend told me how his father spent something like $700 on a 17cc Kawasaki trimmer in the early 80s despite being warned they were no good and it was better to spend more on a larger capacity engine model. Being Dutch -known for being tight with their money- he said no it will do. According to my mate, it was the most useless gutless thing ever and had to replace it with a better not long after. They got a Dolmar which was a good machine but the shaft failed a few years ago, leaving a perfectly good running engine!
A pity Makita had to acquire Dolmar.

17cc is enough to trim a well cut lawn but anything above that would be suspect. I am guessing it was a TD or TG18.

The stihl FS51 is apparently 16cc which should be interesting

Tried the Tanaka again today. I don't even bother moving that main jet blocker knob - leave it in the run position. Prime until all the air bubbles are out of the line (13 times today), full choke 1/4 throttle and it fired up and ran first pull (which is good for any brushcutter let alone a 40 year old one). Push the throttle back to idle and

Yes, please go on.

G'day Tyler ,Bruce and Mf

I was assuming the black choke knob worked the same as on motor bikes especially seeing that Tanaka
manufactured moped engines and later motorcycle engines.

Tanaka History is interesting if you haven't seen it before.

https://www.metabo-hpt.com/us/main-navigation/tanaka-history

Cheers
Max.

go! haha