GeraldRosebery

My Feedback: (14)

After a carb rebuild can anyone advise as to the best initial settings for the Walbro SDC Carb? It comes from a Taurus 62. Right now the low end is open 3/4 turn and the high end really doesn't make any difference to rpm at the top end. It turns a Zinger 22 x 10 at 6300.

Thanks.

Flypaper 2

Gerry:
I start at 1 1/2 turns on both. Thats rich, but the engine will stay running while you adjust it. Don't know what you mean by " doesn't make any difference at the top end" .

GeraldRosebery

My Feedback: (14)

The H needle can be opened to 1 1/2 turns or closed completely and the top end is still 6300. Interestingly, after 1 1/2 turns out the rpm does drop. The engine turning 6300 with the H needle closed and the L needle open 3/4 turn is bizarre to me. The L needle is very infuential. The engine won't start at all at settings over 1 1 /4 and and quits below 2/3 turns out. Beats me. That's why I have ordered a rebuild kit. This engine is new with maybe 1 gallon through it.

(I had a similar problem with my Taurus 52 which uses the WT 76 carb even though the engine was also new. I suspect Taurus used recycled carbs and doesn't bother with a factory rebuild. After a rebuild, however, the needles are set to 7/8 out on the top end and 1 1/2 on the low end, which manufacturer's spec for this carb.)

Flypaper 2

I'd try a carb kit, as you say, and go from there. Some HDCs have a built in accelerator pump and it may being fed from there. If it still acts up give us a holler and I'll dig up an old carb and see what's going on. A while since i've had one apart.

JLB

My Feedback: (2)

That's about as wrong as it gets. A SDC80 usually runs about 1 1/8
on the high end. If it does that after a rebuild I'd be looking for
another carb. That carb is somewhat of a mismatch for that engine
as we usually used them on 80's or 100's.

Antique

My Feedback: (4)

If the SDC is NOT an 80, I'm not the only one that ASSumes.. SDC carbs range in size from 14.27 mm to 19.84 mm..The 80 is 19.05 mm..
ASSumptions galore..The specs from the manufacturer of the WT 76 carb (Walbro) are 1 1/4 turns initally, then tune from there...Maybe the specs from the engine manufacturer (Taurus) are different

GeraldRosebery

My Feedback: (14)

The specs come from Brison for their 3.2 with a WT 76 carb.

The butterfly valve of my SDC has a diameter of 20.5 mm. There is a small restriction in the throat, but it cannot be measured.

stalspin-delete

Gerry, I've been reading all your post about the Taurus engines, which i disagree with. So I contacted them and told them your problems. here is a quote.
" have the gentleman return both engines to Taurus and we will repair them both at no cost".
now thats not too bad an offer.
By the I asked awhile ago if you still had the 52cc and how much you wanted for it, got no reply.
guess you didn't want to sell it.
If It was me I think I'd take them up on the offer.

excaliber

I have been following this thread for awhile with interest because I have a Taurus 4.2 with a SDC 80 on it.
RCign and JLB seem to know something, at least more than most on this thread. So my question if the SDC 80 is questionable as a carb. What would you two fellows recommend.
My 4.2 turns a 24x10 at 6400 on 50:1 Klotz.
I also wonder if this fellow with the problems bought the engines new or used/ just curious. I think the suggestion from Stalspin has merit.

Antique

My Feedback: (4)

The SDC 80 is the best carb, there are no problems associated with it...It works on everything I have ever tried it on, from a G62 to a 120 3W.....And it is the least expensive, abouit $40 retail.....6400 is right in the ballpark for a 4.2....

GeraldRosebery

My Feedback: (14)

Thanks for the input. I am waiting for my rebuild kit. The diaphrams look pretty old. and it was pretty dirty inside. I find that brake parts cleaner, which is pressurized dry cleaning fluid (non-flammable) works very vwell to blast crud out of all the ports and it dries quickly. And yes, I do it outside, as I don't want my liver dissolved either.

I was not complaining about the ground run output on the 62, just the poor transition and stumbling in the air. It was scary.

mglavin

My Feedback: (31)

Taurus Engines does not use recycled/used/abused carbs or any used parts, this is straight from the Bulls mouth... Taurus offers premium products of which I have rarely heard of any problems of end users to date. I have been an advocate of these engines for many years now and feel very confident in suggesting your problems are unique and unusual. Taurus runs and tunes every engine prior to shipping them. If they have any problems or don't meet baseline standards they are not shipped...

I own two TS-62 Taurus Engines with the same Walboro carbs no problem's with them at all.

If you can close the HI needle completely with no effect you have a problem a carb repair kit is unlikely to rectify IMO... Sounds like you have an air leak somewhere to me. I suppose a gasket might remedy the problem but I doubt it, I'd look harder at the assembly, manifold and such.

Several things come to mind, what’s the history on the carb and engine? Has the carb been removed? Carb been opened up, a common problem is attributed to modelers removing the static diaphragm cover plate and inadvertently tweaking the fork on the lever under the diaphragm. Makes the engine act strangely.

Brake fluid is a poor choice for cleaning carb parts, especially plastic and rubber stuff, its too strong and damages these materials. FWIW, Aerosol brake cleaners are not dry cleaning fluid or solvent, and for that matter dry cleaning solvents are flammable TYPE III solvents with flash points from 140*F on up. The most common dry cleaning solvent "PERC" is often associated with parts washing solvents from early on in the days of auto repair; it’s similar but much more refined with chemical stabilizers and costs a lot more...

BobH

My Feedback: (2)

I believe I have rebuilt well in excess of 200 walboro and tillitson carburators and in my experience if the carb was truely "dirty' then the welch plugs were needed to be removed before the ports were cleaned. If you buy a rebuild kit they should be included. To remover them requires a delicate touch with an Awl. The angle of insertion should be steep enough to penetrate the dome of the plug but not contact the body of the carb, less you do damage there.
I can't speak to your particular problem, I think this the same engine you were having a problem with all along? You might be be wise to send the engine to Taurus and have it completely checked out but thats your call. I know a lot about these small engines having spent 15 years in that field, working on and testing them in a laboratory. They are not complicated but they do have nuances that can be over looked by some one less experienced. Just thought you might like to know. BobH.

GeraldRosebery

My Feedback: (14)

I am pleased that your Taurus 62's work well. This engine is well designed and very smooth and quiet. I bought the engine new, but second hand, so Taurus didn't want to know me and refused even to provide any input at all when I called them. Maybe they were having a "bad day" but it truly annoyed me at the time. It is about 18 months old at this point. How the carb got so dirty inside, I have no idea, but there were actually flat metal chips on the screen, which I have never seen before. I always use a fine in-line final filter on the carb line. The diaphrams look old, similar in fact to those I have pulled off four or five year old engines from weed eaters etc. Maybe the carb was new when it was installed on this engine, but then..... As far as an air leak, yes, that is possible. The whole carb multi gasket, huge block, aluminum throttle transfer plate are all prone to air leaks. I used new gaskets and gasket sealer to try and eliminate this as an issue, but it is possible. I had similar problems on a new Taurus 52 and a rebuild fixed them. What's to lose?

The brake parts cleaner I use does not attack rubber or plastic parts as so many car parts are made of thse materials and the product is formulated not to damage them. It does, however, chew up paint. It works great for cleaning your plane too, by the way if it's covered in Monokote or Ultrakote.

stalspin-delete

Gerry, with all the screwing around you've done with those two engines, buying carb repair parts, sending one to C H and then to a engine doctor, it appears to me you would have been further ahead in time and money to just have sent the engines to Taurus.
Man you are stubborn. maybe a pride thing??? But maybe all you have is time and money.
By the way a carb cleaner found in any auto supply store works just great and only $2.99 a sprat can.

Antique

My Feedback: (4)

The best spray cleaner comes from Wal Mart, $.87 for a big can, I buy 8 at a time..I think the brand is Super Tech, comes in a black can....

Brano1025

Yep, I buy that Super Tech carb cleaner too. Works great and you get a lot.