Hot start issue....Sachs-Dolmar 112

[satdiver]

Hello all,
I've got an issue with an old saw of mine, it's a Sachs-Dolmar 112. It starts on the first or second pull and runs great, but if you shut it off or if it quits, it won't re-start till it sits and cools for a bit.

Any ideas?

This is what I've checked/done so far:
fresh fuel
fresh plug
fuel filter not clogged
carb taken apart and cleaned/tuned

This thing has me stumped at the moment. I thought maybe the coil was going bad, like it would run till it heated up then open but it still has spark when hot.

Any help would be greatly appreciated! :help:

 

[cuttinscott]

when its hot and wont start check for spark




Scott

 

[nmurph]

it sounds like a coil. spark is not a guarantee that all is well with the coil. you can get spark out of the cylinder, but put compression in the equation and you may not have a hot enough spark.

 

[satdiver]

Thanks Scott, I did just that and it does have spark, but still does not start.

 

[dans3kgt]

Have you tried cracking the gas cap ?maybe the vent is niot working?Just a thought.

dan

 

[satdiver]

it sounds like a coil. spark is not a guarantee that all is well with the coil. you can get spark out of the cylinder, but put compression in the equation and you may not have a hot enough spark.

That's what I was thinking also but there have been just a couple of times that I've been able to get it started while hot after pulling it many, many times!
Could this be a vapor lock issue?

Thanks for your help!

 

[satdiver]

Have you tried cracking the gas cap ?maybe the vent is niot working?Just a thought.

dan

I'll give it a try Dan, thanks

 

[stihlhead]

That's what I was thinking also but there have been just a couple of times that I've been able to get it started while hot after pulling it many, many times!
Could this be a vapor lock issue?

Thanks for your help!

It's a coil issue. When you pull it alot the fins are cooling the coil down. Enough pulls and the coil cools down enough to generate a decent spark. I would change the coil. Just my .02

I have a Husky 40 in the shop now waiting for the coil to get here with the same problem. It would fire on the 2nd-3rd pull when it was cold, 75th-100th pull warm. The coil finally went all the way out and it doesn't start at all.

 

[TRI955]

Have you done a compression check??? Compression only goes down with temperature....

 

[cuttinscott]

I assume it is a orange top 112? And has Point ignition. When you said it had spark was it a bright BLUE or was it not so blue and more yellow/gold??? If Spark is the Issue Order a electronic ignition coil from a PS6800 it will fix all and any issues as well as run and start better. If Spark is not the issue I would be checking the vent system of the saw the tank vent/fuel nipple is under the air cleaner elbow the line off the right side is your fuel line and is 1/8" ID tight fit on the nipple the VENT line comes straight up off the left side of the tank nipple and it has the 1/8" barb BUT uses a 3/16 ID Hose that routes to the left and under the carb adjustment guide block down through a hole in the crankcase. If the line is too tight on the nipple the tank WILL NOT VENT Properly..

Hope this helps


Scott

 

[satdiver]

update

All:

Got the saw running this afternoon and had it running for about :30 or so, making a few cuts in a 8" limb. I was able to shut it down and start it back up immediately 4 or 5 times. As soon as it sat for more than a few minutes, NOTHING! Would not start at all.

It seemed to be very rich on the low side so turned it down while running and the L screw is almost bottomed out.

Checked the vent hose and opened the gas cap (no pressure build-up) and still nothing would help it start. Compression is also good.

I'm still thinking vapor lock or coil is failing? Anyone else?

 

[Metals406]

Lack of adjustment on the carb could mean an air leak. . . Have you pressure tested? It would also make the saw get really hot.

 

[satdiver]

Lack of adjustment on the carb could mean an air leak. . . Have you pressure tested? It would also make the saw get really hot.

I haven't pressure tested, yet, and it doesn't run any hotter than normal.

As far as adjustment, the L screw is almost all the way shut. I mean it's barely cracked open (1/8 turn). Any more than that and it runs rich.

Thanks for the help.

 

[Metals406]

I haven't pressure tested, yet, and it doesn't run any hotter than normal.

As far as adjustment, the L screw is almost all the way shut. I mean it's barely cracked open (1/8 turn). Any more than that and it runs rich.

Thanks for the help.

That definitely isn't normal. . . 1/8 turn should be really insufficient to feed the saw.

Rebuild the carb and replace the fuel line and tank vent line with some Tygon. Also, as said earlier, the vent and fuel line meet on a white plastic "manifold" that kinda sits in front of and below the air filter side of the carb.

It's just kinda friction fit in there with a crappy little gasket, a poor design really. I had to reseal with Three Bond 1194 (though you could use something like Seal-All or JB Weld).

I'd also check to make sure you're not sucking air from somewhere! Check the jug bolts to make sure they're not loose, etc.

It's gonna have to be a process of elimination.

 

[satdiver]

That definitely isn't normal. . . 1/8 turn should be really insufficient to feed the saw.

Rebuild the carb and replace the fuel line and tank vent line with some Tygon. Also, as said earlier, the vent and fuel line meet on a white plastic "manifold" that kinda sits in front of and below the air filter side of the carb.

It's just kinda friction fit in there with a crappy little gasket, a poor design really. I had to reseal with Three Bond 1194 (though you could use something like Seal-All or JB Weld).

I'd also check to make sure you're not sucking air from somewhere! Check the jug bolts to make sure they're not loose, etc.

It's gonna have to be a process of elimination.

Thanks, I think it may be sucking fuel past one of the carb gaskets or somthing because its getting way too much fuel on the L side!

What did you have to re-seal? The white manifold to the saw body?

 

[Metals406]

Thanks, I think it may be sucking fuel past one of the carb gaskets or somthing because its getting way too much fuel on the L side!

What did you have to re-seal? The white manifold to the saw body?

I used Three Bond 1194 (Honda Bond, Yama Bond are all the same). . . Seal-All is fuel proof, and can be found online or in a hardware store. . . JB Weld would be a little more permanent of the three.

It also wouldn't be a waste of time to order the PS-6800 ignition and coil setup from Scott (cuttinscott who posted earlier). He probably has your carb kit, and Tygon too. . . Can't hurt to PM him and ask?

 

[pioneerguy600]

The Sachs Dolmar 112 uses a Tillotson HK carb, it is well known that these carbs have a plastic module body assembly, when the seat for the metering needle goes bad no amount of carb rebuilding can save them. Your saw exibits all symptoms of this malady. I would bet a new carb would cure this problem, I have fixed a good many of them that had this problem.
Pioneerguy600

 

[andrethegiant70]

The Sachs Dolmar 112 uses a Tillotson HK carb, it is well known that these carbs have a plastic module body assembly, when the seat for the metering needle goes bad no amount of carb rebuilding can save them. Your saw exibits all symptoms of this malady. I would bet a new carb would cure this problem, I have fixed a good many of them that had this problem.
Pioneerguy600

I'd look into this and forget the concept of an air leak for now. You're getting too much fuel (for the needle setting) not too much air. The saw has an issue, but it does NOT appear to be an air leak issue.

 

[satdiver]

The Sachs Dolmar 112 uses a Tillotson HK carb, it is well known that these carbs have a plastic module body assembly, when the seat for the metering needle goes bad no amount of carb rebuilding can save them. Your saw exibits all symptoms of this malady. I would bet a new carb would cure this problem, I have fixed a good many of them that had this problem.
Pioneerguy600

Thanks guys, I'm checking into this more as this seems to be more in line with the problems its exhibiting. Today, running it without the air filter and the L screw just cracked open about 1/8th, when I hit the throttle, it'll blow a little fuel out the air intake. Getting way to much on the low side.

My question is this, can the plastic piece where the needle and seat are be replaced or the entire carb? Can I get one from a Dolmar dealer or is there a site sponsor here that I should contact.

Thanks for the help!

 

[pioneerguy600]

Thanks guys, I'm checking into this more as this seems to be more in line with the problems its exhibiting. Today, running it without the air filter and the L screw just cracked open about 1/8th, when I hit the throttle, it'll blow a little fuel out the air intake. Getting way to much on the low side.

My question is this, can the plastic piece where the needle and seat are be replaced or the entire carb? Can I get one from a Dolmar dealer or is there a site sponsor here that I should contact.

Thanks for the help!

The plastic part can be found through Tillotson but it will likely cost as much as a new carb , check with the Dolmar dealer to see what they can do. The carbs were running around $50. just a short time back.
Pioneerguy600