DOLMAR 7900 - is it a piece of JUNK?

[ncfarmboy]

Trim the limiters on h/l needles adj to 1 turn. Start saw. Adj low needle. If this doesn't fix pull carb and check needle height if it's high will flood, if low will be hard to start. Mine also takes a very brisk pull. Putting a Stihl "D" handle on it when I get caught up. Oh! absolutely LOVE mine.
Shep

 

[WKEND LUMBERJAK]

Like comedy, it's all in the timing. Using fresh mix, when cold: ignition on, fast-idle set, choke on. Push purge bulb until essentially full of fuel; you don't mention this. Crank until first pop- listen CAREFULLY- smoke means it's been there. Choke off. Crank until it starts, no more than 3 cranks.
Should then be running @ fast idle.
If not, there's something wrong with the saw or you. Consult dealer for advice. Or ask a bud to try. Seems to me, you're just not picking up on what it's telling you. That includes reading the plug.

My 7900 does not have one. primer bulb that is.

 

[WKEND LUMBERJAK]

I have to agree with 2 previous posts You have to Pull the rope Like you mean it on these saws.

 

[Hugenpoet]

My 7900 does not have one. primer bulb that is.

+1 My 7901 doesn't have a primer. It is however my easiest starting saw. Three puls with chole on and it always pops, then one pull with choke in and it always starts. Runs like the proverbial ***** ape.

 

[NathanA]

If you havn't already try starting with the decomp out. On my dolmar the decomp was working to well and all the saw would do is smoke out the exhaust but not start if you pulled the decomp out would start straight away fitted new decomp problem solved. It was a new saw that had done hardly any work

 

[huskystihl]

I can't speak for the 7900 as i've heard many great things about them but I also posted many threads over the 5100's that were outlasted by homeowner stihls. Chances are the advice on flooding is true but I say this with respect if thats the case maybe you should rethink owning a saw that powerful, my 13 yr old son is helping out when he can and outside of rope tending his primary job is refueling, touching up chains and making sure that when needed the bigger saws are warmed up and has no problems firing a 90cc saw with no decomp needed. On another note all the dolmar dealers around my parts dumped them for service issues. I compare the dolmars to the 6.0 liter powerstokes, when they are running they're great but thats about it!

 

[Walt41]

Have you tried another plug? I've seen cases where the plug will have spark at the gap until it's under compression and then it shorts out. Might be enough to cause a little smoke but not enough to run. Hold the plug vertical with the electrode down - I've seen the insulator break off, slide down and cover the gap.

Thankyou! I was hoping post 2-3 would say that, not #19.

 

[slowp]

I take it you bought this new from a dealer, if so have you taken the saw back to them and described your problems?

Good luck

I'd go with that, except look where he has himself living. Lester is a gated off deserted town up in the mountains near Stampede Pass. I thought it to be an abandoned town. I guess it isn't. Anyway, he would have to take a snowmobile to get to town. I don't think that trains go that way? That's how they used to get in and out of Lester in the winter.

 

[gmcman]

You mentioned that you went to get some ethanol-free fuel, if i'm not mistaken, we get this fuel from Canada and their standards are different. What I would try is to go get some fresh 89 or 93 octane fuel from a known busy station and mix with some good oil.

Also put a new plug in there to eliminate the possibility of a fuel-fouled plug. Even with the plug dry, once unleaded fuel fouls a plug it's pretty much toast unless you get in there with some sandpaper and clean it up. I agree with double-checkng the factory settings, may run rich but will at least have enough fuel for a cold-start.

 

[classic rider]

I had the exact same problem with my 7900 and the problem was the low mixture adj. was to lean, turned it out (counter clock) about 1/3 turn and now it runs and starts as it should, also needed to set the idle a little higher after low adj.

 

[Vibes]

My 7900 flooded real easy when new. The problem was ME trying to start it with the ON/OFF switch in the wrong position. I was trying to start it with the switch on the opposite side of the little STOP sign. There is that little arrow on the other side of the switch pointing in the diection of STOP. Confusing sounding, but believe me, I didnt have another problem after I wrote RUN on the side of the handle for ON with a Sharpy Marker. Problem solved for this blind DUMBAZZ!!!

I've only done a little tweaking of the carb on mine in 5 years. Still running the original sparkplug.

My guess for this one is bad gas.

 

[3000 FPS]

Please excuse my ignorance 3000fps, low carb. setting? Is that the throttle setting that is supposedly set a bit above idle when the choke is pulled out? If so, that sounds quite logical to me - seems like it may possibly be the case the way it is acting.

As fer Wendol, yes I pull the sunafa##### a very quick brisk pull - I may be an old fugg but I know enough and can still give it a very fast, quick pull, thanks in part to the compression release thanks fer the input.

Most of these carbs have 3 settings. One is a low setting for when the carb is at idle and when it just comes off of idle to accelerate. One is a high setting for when the saw is at full throttle. Then there is a stop adjustent that is a screw that provides a stop when the throttle is released which sets the idle rpm. The first two are needle jets that actually affect the mixture of gas going into the carb. Sometimes if you look on the cover or on the carb itself you will see a H or L indicating which is which. If the low setting is to lean because of emissions standards from the factory they can be very hard to start because they just do not get enough gas. Turning a jet out or CCW richens the mixture. Like what previously mentined here on by one of the guys sometimes all it take is a 1/3 of a turn.

 

[Bluefish]

Look up the town he lives in. He may be the only resident.

 

[7sleeper]

I donot believe that it is a carb setting problem. What you assumed in your first post to be smoke cumming out of the muffler is, I believe, really a very flooded chamber and the "smoke" was in reality a "gas mist". In my experience Dolmar chainsaws can flood very quickly. So you are ripping along on this starter rope waiting for that first pop while flooding that chamber even more and more. Just yesterday the same happened to me. Pulling on the starter rope waiting for a pop and seeing "a mist/smoke" come out the muffler.
Easy diagnose => quick fix.
1. unchoke and pull the trigger once to get the half choke off!(if you don't and unscrew the spark and pull the rope you will just keep on flooding until the fuel tank is empty!) 2. unscrew the spark plug and air dry it + pull the starter rope a few times to get the cylinder dry. 3. restart without choke and be ready for a ruff start till all the excess gas & oil is burnt off. After running it a few minutes its a non existing problem anymore.

Good luck

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[blsnelling]

There is no half choke setting. What you're referring to is fast idle. I recommend having the throttle wide open, as I detailed last night. You want maximum air going into the engine.

 

[blsnelling]

Go pull the plug. If it's wet, leave it out, lock the throttle wide open, and pull it over rapidly several times to help clear it out. Then check for spark before reinstalling the plug. Reinstall the plug, leave on fast idle, no choke, and pull until it starts. If it still won't start, I'd pull the carb off and go through it.

Here's what I recommended.

 

[7sleeper]

Sorry BL, I named it wrong . But I just read all your comments again and admit we are talking the same language just using different words.

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[Fnfal]

Thanks for all the diverse repies. Heading out in a short while to troubleshoot the problem, starting w/pulling the plug. It really should not be the gas, as it was hard starting when cold the first time I used it (w/non ethanol gas) when brand new. Bought fresh ethanol gas for it yesterday from a different (local) station using the Stihl ultra oil as I did the first time. The plug should have been good to go off the start cause it was running great when I shut her down last time. I tend to shy away from fiddling w/the carb adjustments as I'd probably end up really messing the thing up. I'll have a full report later today on what I found and hopefully no more questions. Thanks again for all the input

 

[Fnfal]

Push purge bulb until essentially full of fuel; you don't mention this[/B

Went out today in the daylight to pull the plug. Put my spectacles on. Weird piece of flat rubber on the side, hmmmn. Had no idea it had a stinkin' primer thingy - did'nt think chainsaws had 'em. Too old school I reckon I am. Pushed that sucker a couple three times, choke, no throttle, Whaddaya know? It runs:msp_biggrin:

DANG that saw sounds nice!

I guess title of thread should have read: I AM AN IDIOT !

Thanks so much CTYank and to all others who gave their input.

Now instead of being a frustrated idiot I'm a happy idiot

 

[7sleeper]

Welcome to the "I am an idiot" club.

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