im trying to tune the carb on my 7900 as the low speed was running a little too rich . i can get it to where it sounds good accellerates good .. but every once in a while when its sitting there it will just die.. im not really sure if its starving or loading up and dying . it dies real quick though .. Think the low speed is still off a ways? or could there be something else causing this ?
7900 carb adjustments
- Thread starter arborman
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skwerl
Will Climb for food
Get the saw idling and let it sit for 20 seconds. Then pick up the saw and quickly tip it nose down. If the saw dies then it's too rich.
yea i tryed that test.. i didnt wait the 20 seconds though.. ill have to try that.. last time it was running like this i switched the plug out .. and where we were working the place the guy went to get my plug only sold champion.. im going to get an ngk for it again before i tune it .. dont know if that will make a difference but it will make me feel better either way. Think the tank vent could be having problems ? froozen maybe ?
ok i got it to where it will pass the dip test.. however when you turn it on its right side it seems to be running lean and when you turn it on its left side it seems to load up a bit ? is that normall ?>
skwerl
Will Climb for food
My buddy Tim was having some wierd issues with his 5100 carb. Try spraying it with wd-40 while it's idling (without getting it in the air filter) and see if it dies. My personal suspicion is that Dolmar has some QC issues with the cheap Chinese carbs.
cuttinscott
Addicted to ArboristSite
Their was a carb upgrade for these saws the early models would wear the throttle shafts and choke shafts this was not only a Dolmar prob. I've seen many Huskies with the same issues although we prototyped new carbs for Dolmar and Zama and these newer carbs have nickel plated shafts and are much more durable. Look to see if the shafts are tight or their is any play most noticible on the right side where the mid throttle mates with choke. The new carb part # is Dolmar 038153021 PM me for a price
Scott
Scott
NorthWoods
ArboristSite Lurker
Question for cuttinscott:
Scott:
When did the 038153021 carb get put on the production line. I bought a Makita 7901 a couple of months ago and am wondering if it has the updated carb..
Dave
cuttinscott said:
Scott:
When did the 038153021 carb get put on the production line. I bought a Makita 7901 a couple of months ago and am wondering if it has the updated carb..
Dave
cuttinscott
Addicted to ArboristSite
Dave, Makita's are generally older stock than the Dolmar line as far as production. Let me know the first 5 digits of your serial #
Scott
Scott
166
Addicted to ArboristSite
Here is the older style Carburetor on the PS-6400, PS-7300, PS-7900
This is the new style Carburetor on the PS-6400, PS-7300, PS-7900
This is the new style Carburetor on the PS-6400, PS-7300, PS-7900
well it looks like I have the old carb.
Lets see i've replaced the oil pump and oil lines, I need a new chain tensioner, and my carb going to go out. Anyone want a EHP7900.
Lets see i've replaced the oil pump and oil lines, I need a new chain tensioner, and my carb going to go out. Anyone want a EHP7900.
Andyshine77 said:well it looks like I have the old carb.
If it's FREE to a good home, I'll pay for the shipping
cuttinscott
Addicted to ArboristSite
Andyshine77 said:well it looks like I have the old carb.
Not all carbs will fail only saws that have had loads of hours and lots of triggering action
Also these carbs are not very expensive if you figure parts and labor to rebuild old ones it is very cost effective just to swap.
Scott
Kind of glad I went with the Husqvarna.Andyshine77 said:well it looks like I have the old carb.
cuttinscott
Addicted to ArboristSite
Bad E said:Kind of glad I went with the Husqvarna.
I HAVE SEEN MANY HUSKY'S WITH THIS SAME ISSUE!!!!!!!!
Scott
166
Addicted to ArboristSite
Andyshine77 said:well it looks like I have the old carb.
Most of the Carbs & Chain Tensioners we have installed at Little to No Charge to Our Customers!!
Steve
redprospector
Addicted to ArboristSite
Andyshine77 said:well it looks like I have the old carb.
I don't care what a man has, if you use it parts will break and wear out. I don't think anyone has come up with a cure for this.
Andyshine77, what do you want for it?
Andy
Sorry everyone I was just joking the saw is not for sale. The 7900 is a good saw, however the saw does have some problems that it should not, in my opinion.
BTW The saw has only burnt 20 tanks of fuel. It's in like new condition.
The 7900 is a good saw, however the saw does have some problems that it should not, in my opinion. BTW The saw has only burnt 20 tanks of fuel. It's in like new condition.
yea i like the saw.. even though it has this problem i still like the saw , i checked the linkage and shaft down there bye where the choke connects and nothing seemed loose.. took it to a dolmar dealer.. he ran it said the saw runs great.. then i had him tip it from side to side.. and it died on him.. he said its wierd and hes never seen anything like it before.. and that hes going to have to call dolmar about it . i mentioned that shaft that goes through the carb to him and told him they have an update for that part. but he didnt seem to take me real serious about it.. maybe hel find out tomorrow when he calls them.. Anyone know roughly how much a new carb would cost?
i may just go that route with it if its going to be cost effective .
i may just go that route with it if its going to be cost effective .
166
Addicted to ArboristSite
arborman said:
From what you're saying now it sounds like you have a cracked fuel line.
Is your fuel line Green or Black? I have seen quite a few of the Green fuel lines break.
Part # 038 114 051 Black Fuel Line
Steve
