Thread: partner 1250 power head

Originally Posted by pjt

Hi all,
have a couple of questions, somebody will have an idea
Got this concrete saw at auction, has had a hard life but I think it will go again, fixed the pull start today, added some washers to behind the starter engagement links

Not sure about the coil tho, doesn't seem to generate any spark, I put the multimeter on the coil lead and best I could see was maybe 2 volts, ( I assumed DC) this doesn't seem to be much, How much should it be and if it's ratshit where's a good place to get a replacement? .

A standard multimeter won't be able to measure the high V generated by a coil. All you can hope to measure with a multimeter is if the coil has continuity or a short. Also the air gap between the fly wheel and the coil might need resetting.

Thanks Bob, I imagine that the voltage spike generated might all happen too quick for the multimeter to see it I will test for a short and continuity.
Does the speed at which the fly wheel rotates have an effect on voltage generated? just thinking that I first was turning it by hand but then by the pull start.
The air gap, Any idea on what it should be? I'd guess with a large gap the coil may not "see" the flywheel and a small gap, I don't know, maybe a timing issue, scraping

Pete

air gap should be approximately 20 thou or 0.5 mm or slightly less, I know of some people setting them with a cigarette paper but really this is too close. if you are using a feeler gauge however make sure that it conforms to the radius of the flywheel accurately or you will find you are setting it to a distance greater than desired.

Originally Posted by Travis Edwards

air gap should be approximately 20 thou or 0.5 mm or slightly less, I know of some people setting them with a cigarette paper but really this is too close. if you are using a feeler gauge however make sure that it conforms to the radius of the flywheel accurately or you will find you are setting it to a distance greater than desired.

Thanks Travis,
What effect does the gap have on engine performance? I assume that it would be one of timing when the spark occours


Pete

are you going to turn it in to a chain saw or keep it concrete

Originally Posted by itsposs

are you going to turn it in to a chain saw or keep it concrete

It will stay as a concrete saw, from it's looks it's a Husquvarna in disguise, it has the oil filler formed in the side cover but no plug so I'd say no oil pump but I could be wrong.

Pete

Originally Posted by Travis Edwards

air gap should be approximately 20 thou or 0.5 mm or slightly less, I know of some people setting them with a cigarette paper but really this is too close. if you are using a feeler gauge however make sure that it conforms to the radius of the flywheel accurately or you will find you are setting it to a distance greater than desired.

I had a look at the gap, didn't measure it, just eyeballed it and it's about awww yeh um 1/2mm or so so I'll leave that as it is unless I have to check it further.
Checked coil for continuity, that's allright, measured at 6.61kohms, which to me says lots of winding intact (not shorted) but that's only a wild stab in the dark by me, Does anyone know what value they shuold be? Spose I could compare it with the 3120.


Pete

I thought some of those concrete saws went up to 150 cc - 160 cc

Originally Posted by itsposs

I thought some of those concrete saws went up to 150 cc - 160 cc

The 1250 according to mytoolstore.com specs says it's 119cc 5.8kw.

Pete

ooooooh I like that site

Originally Posted by pjt

Thanks Travis,
What effect does the gap have on engine performance? I assume that it would be one of timing when the spark occours


Pete

the gap should not have too great an effect on spark timing, it is mostly just there so that the flywheel will not foul. you dont want to be too far away however or you run into reliability issues.

the timing is altered by moving the magneto/coil radially around the flywheel. have you checked your plug lead for continuity, and tried a different plug.

may sound like I am being a smartass but when you tested the spark did you have the plug grounded on the head of the motor?

another possibility is your ignition switch not switching. one of my stihls does this since I put an aftermarket airfilter on it you flick it to the kill position but it doesn't die unless you give the switch a bit of a jiggle.

*edit* notice there is a fair bit of ver degris on the plug connections i.e. where the blue wire plugs to the ignition pack, may pay to clean all contacts and maybe even replace the blue wire if it is badly corroded.

Originally Posted by Travis Edwards

have you checked your plug lead for continuity, and tried a different plug.

may sound like I am being a smartass but when you tested the spark did you have the plug grounded on the head of the motor?

another possibility is your ignition switch not switching. one of my stihls does this since I put an aftermarket airfilter on it you flick it to the kill position but it doesn't die unless you give the switch a bit of a jiggle.

Thanks Travis,

When I checked the coil continuity I had to include the lead as it seemed to be moulded into the plastic of the coil so the 6.61 kohms is the resistance for coil+lead.

Yeh I know what u mean, I first tested without using plug, set lead up close (2-3mm) gap to the head so I should have seen a spark.

I did wonder about the switch, that I will have to check further....

Pete