Chainsaw Repair
Husqvarna - Stihl - Poulan - Jonsered - Dolmar chainsaws and more => Efco Olympyk Oleo-Mac => Topic started by: Old Iron Logging on March 06, 2011, 08:34:05 pm
-
Carb is a Walbro HDA 205-C. Set to factory spec the saw turns 12,700. Manual says to set saw to 13,500 post break-in. Trouble is, as you make the carb setting leaner, the saw looses rpm. With the H closed off saw holds 12,000 rpm. Acts like a fuel governed carb, but see no governor on it. Tech at ESF saws the carb is not governed. Any ideas?
-
Do you have another carburetor to bolt on to eliminate the one on it now? To me if you close off the hs needle it should stop fuel supply, so it shouldn't turn 12,000 rpm. Sounds like the main jet is getting fuel from somewhere else because I dont see the low speed jet suppling enough fuel to turn that rpm. The last hda i remember had a brass plug over top of the main jet, I wonder if this is leaking? Fuel is getting to the engine somehow to run wide open throttle.
-
I tried it with another used carb and got the same result. That had me thinking governor. But unless they are built different now I can see no evidence of one. Going to try a new carb today.
-
Could be gov inside car. Had 084 carbs that had some kind of limiter in them. Brass jet type thing inside the carb itself, that flooded them out like the outside brass gov we normally see on carbs. JB was used to block orifice ;) has to be something better to use out there.
-
From this ill it appears to me that there is a governor under the idle adjustment screw. Am I reading this correctly? Look at part #s 17 and 33
http://wem.walbro.com/walbro/product.asp?CategoryName=944&Series=HDA&partnum=HDA-205-1&GroupName=Chain%20Saw&FamilyName=EMAK
-
I've been looking at that too, it appears the hda series has the option of a governor.
-
I just looked the carb over again and see nothing on the outside.
-
17= Governor Kit ???
-
I also see the circuit plate as a possibility. Fuel has to be feeding the engine to see 12000 rpm. Kinds sounds like a governor to prevent leaning out on topend. I don't see the low side delievering that much fuel. Does the 205c have the circuit plate?
-
Yes the 205 has a circuit plate.
-
Art,
Welcome to the EPA PHII carbs, I experience the same problem when all the husky strato saws started showing up, get the saw good and warm (aka let it idle for 15 min) then cut a few rounds, and then start adjusting. They do not react like older carbs, and the tech info is for the birds especially when they state max rpm is 12500, but the saw gets set at 13500, and the saw is limited at 13100 kind of crap.
When I get stumped i pull the high and low screws and re-install at the base settings then go from there.
-
Yeh, things are sure different than in the old days. I throw the tach away and tech charts. 10 minutes in the woods and I can get them running great. I only want more RPM out of this saw as I plan to race it. A different carb will cure the problem.