dolmar 120 ignition

[038mag]

hey, i have a dolmar 120 that has no spark. and i am told that the husky480 bosch ignitions will work on the dolmar, or even the 056/045 stihl.. well my question is will the SEM 480 coil work? i have one of those just not the bosch, thanks

 

[sachsmo]

Which ignition do you have on the saw?

Is it a regular 120, or a 120 Super?

The 120 Supers had both the Bosch and the SEM (depending on year of manufacture)

You will need the right flywheel to match the ignition system SEM ignition needs the SEM flywheel, Bosch ignition needs the Bosch flywheel.

 

[038mag]

it is the regular 120..47mm piston. i have a super as well. the super has a black plug wire and the regular 120 has a grey one, not sure that helps. i have a good husqvarna 380 ignition and flywheel, will that mesh with the dolmar? what about the starting pawls on the recoil?

 

[sachsmo]

The Supers had a 49mm piston and a 36mm stroke. Tre regular 120 had 47mm piston and 35mm stroke.

You really need to pull the flywheel to see what you have under there.

The Bosch is known to short the 'kill wire".

They can be stubborn even with a good puller, be careful!

 

[038mag]

can a guy fix the short in the kill wire? or is it internal? and yea i just put a new piston in my super. 49mm. and put the the regular metal tank on the super. i didnt like that primer bulb ****. haha also put a full wrap handle on it,,,looks way cool. also do you know what the MX means in 143mx? i just traded a ms180 for this dolmar 143mx, it runs great but has no throttle linkage lol

 

[sachsmo]

Ain't sure what 'MX' means. I do know from some literature Torino Cobra posted in the Sachs Dolmar stickey, that the MX was lighter 'plastic tank' and had a bigger carb?

I always thought 'MX' stood for 'moto cross'?

I have repaired several Bosch ignitions, but you need to pull the flywheel, the short is usually where it passes through the case, or where it rubs on the metal frame where the 'potted' electronics are.

By the by, you stole that 143, them are some stout saws when everything is right on them!


Got any pics?

 

[sachsmo]

See the one 'circled' in the bottom right?

That's the kill wire, once you remove the module from the case you can see if it has shorted somewhere along the route.

The module is slotted for timing adjustment, it would be wise to put a punch mark on the case and module to get it back (if it was set right to begin with)

Those other two short wires marked with a box are prone to loosing their insulation also.

On the short ones I use 'tape in a can' or some RTV to insulate them.

Actually the bare wires are seldom the cause of no spark (as long as they are not touching the metal)


Of course this only applies to the Bosch, the SEM is totally encased (but the kill wire could still be grounded along the way)

 

[038mag]

ok great im gonna pull the flywheel off tomorro and look it over, and yea ill upload pix of my 143, and my finished 120 super tomorrow. thanks a bunch, o do you have a throttle linkage for that 143? i need one thanks

 

[sachsmo]

ok great im gonna pull the flywheel off tomorro and look it over, and yea ill upload pix of my 143, and my finished 120 super tomorrow. thanks a bunch, o do you have a throttle linkage for that 143? i need one thanks

Probably?

I would guess it is the same as the 123-143?

I have several old concrete saws laying around as well.

Ill take a look next time I go out to the shed.

Pretty fond of the 143s, if you ever want to unload it you can always send me a 'conversation'.

Of course pics are mandatory.

Do you have a proper puller for the flywheel?

Made my own it works on nearly every flywheel that has the 3 holes at 120 degrees.

(see it beneath the spark plug wire upper left o' the box?)

 

[038mag]

yea i think i read that one of the concrete saws was the samw part, but also said the 133 was the same, idk. not enough info out there on these saws, like the stihls and huskys. yea i just use a steeing wheel puller with long grade 8 bolts, it works pretty good, but that thing you have looks sweet and way more practical.

 

[038mag]

i tried and tried and could never get that flywheel off that 120. idk what to do, does anyone have the SEM flywheel

 

[foggysail]

i tried and tried and could never get that flywheel off that 120. idk what to do, does anyone have the SEM flywheel

NO EXPERT HERE...... but will share my experience with the 056. First, I found that placing a ball peen hammer or a similar tool on the shaft end and giving it a sharp blow with a hammer will quickly pop the flywheel with no problems. I tried pullers first and got nowhere.

Next, after you do get the flywheel off, if your ignition resembles the one pictured in post 7 above, it may have the common failure the 045 & 056 suffer. I will be posting shortly what I hope is a solution to this problem which I have discussed earlier here in the forum. And as others have suggested/warned, the shut off wire's insulation deteriorates to expose a bare wire which can also prevent the ignition from functioning if it shorts to ground. Patience!

Foggy

 

[Poleman]

Try a steering wheel puller. That's what I've used on mine....still had to do some tapping on it with pressure on it from the puller to get it off. There a bugger.

My problem was the detererating wire covering also. My parts saw I was going to use had a Nova modual. I found that interesting.

 

[Daniel Latner]

View attachment 333916


See the one 'circled' in the bottom right?

That's the kill wire, once you remove the module from the case you can see if it has shorted somewhere along the route.

The module is slotted for timing adjustment, it would be wise to put a punch mark on the case and module to get it back (if it was set right to begin with)

Those other two short wires marked with a box are prone to loosing their insulation also.

On the short ones I use 'tape in a can' or some RTV to insulate them.

Actually the bare wires are seldom the cause of no spark (as long as they are not touching the metal)


Of course this only applies to the Bosch, the SEM is totally encased (but the kill wire could still be grounded along the way)

How do you set the timing?

 

[Daniel Latner]

Probably?

I would guess it is the same as the 123-143?

I have several old concrete saws laying around as well.

Ill take a look next time I go out to the shed.

Pretty fond of the 143s, if you ever want to unload it you can always send me a 'conversation'.

Of course pics are mandatory.

Do you have a proper puller for the flywheel?View attachment 333917

Made my own it works on nearly every flywheel that has the 3 holes at 120 degrees.

(see it beneath the spark plug wire upper left o' the box?)

That's a nice puller. I just found a thin piece of metal to fit under the flywheel and used the longer screws from the starter assembly to pull mine.

 

[038mag]

The 120 shares the Same SEM ignition as the 123/133/143 and 309/343 chop saws.
Makita dpc 7000/9500
Wacker bts 11/11/13
Stihl 056
Husky 380/480/2100/298/2101
And some 041 stihl

Flywheels on the dolly chop saws will work on the chain saws. The dolly 120 flywheel will work on the bigger saws too but have to change the fan

 

[weedkilla]

Don't know if it helps - but I recently made a throttle linkage for my 6000i out of a stainless bicycle spoke and it's just about the perfect material. I had the advantage of copying a broken linkage though.

 

[sachsmo]

How do you set the timing?

What can your fingers take?

 

[sachsmo]

i tried and tried and could never get that flywheel off that 120. idk what to do, does anyone have the SEM flywheel

.....Pre-load your puller then heat the aluminum around the flywheel bore.

If you get her hot enough it will 'tink' right off in a minute or two.