Muruyama Blower/sprayer

[lefty]

I'm kind of at a loss for where to look next, why I'm wondering about the coil. Can't think of anything else.

[KE4AVB]

He's using 50:1. The spark arrester is clean.

When I said infinite resistance, I really don't know that. I just know that I got no reading with the mega ohm setting, which is my highest setting.

Here's a pic. The small wire at the bottom goes up through the grommet and connects to the coil. I'm getting no reading between the end of that wire and ground.

https://photos.app.goo.gl/gEqS97WHgA52UwBW6

Your are suppose to get a reading on this wire unless the kill switch is active. The ignition primary (Kill terminal) to coil's metal frame should have a fairly low resistance. With engine I doubt you have a coil problem.

When you clean and rebuilt the carburetor you did reset the metering lever and retuned?

BTW here what I found on your meter.

[lefty]

Your are suppose to get a reading on this wire unless the kill switch is active. The ignition primary (Kill terminal) to coil's metal frame should have a fairly low resistance. With engine I doubt you have a coil problem.

When you clean and rebuilt the carburetor you did reset the metering lever and retuned?

BTW here what I found on your meter.

I'm getting very high resistance there. Are you saying that my meter may be bad? It seems to give me good readings everywhere else I test it and I've never had a reason to doubt it. I suppose I could pick up another one.

I did not reset the lever. I did install a new needle, lever and pin. I don't have a lever gauge, which I plan to remedy now.

[KE4AVB]

Yes meters do get damage especially in resistance mode when high voltage is applied. But it simple to test the meter. Just test against a known resistance. I personally have toast a few over the years by not paying attention. One of the reasons I brought a clamp amp module for my meter.

Setting the metering it is important but I can't which OEM carburetor it is. Zama is the easiest as most can set using a straight edge but Walbro are harder and do require one of the two gauges they have now. The old W tool is still more commonly used one but I have been using the new one this year on several chainsaws.

[lefty]

I just installed a new battery and tested it.

20K setting, I read 1.99 on a 2K resistor.
20K setting, I read 10.10 on a 10K resistor.

200 setting, I read 102 on a 100 resistor

2K setting shows .221 on a 220 resistor

2M setting showing .809 on a 1M resistor (my resistors are not high quality. Came in a cheap kit but seem to be ok)

I think that's good?

But I'm still showing higher than 2M ohm on the meter when testing the primary. It still shows a 1 (which would be OL on yours), which I believe means it's reading higher than 2M resistance, possibly infinite?

[KE4AVB]

Yes it sounds like your meter is okay.

Resistance do have different tolerance ranges which depending on tolerance range can be off by as much +-20% of the indicated value. Otherwords a 1000 ohms can be anywhere from 800 to 1200 ohms if it has 205 tolerance range.

I try to use resistance tolerance of 5% or less but it is not always possible. Some of the things I use to repair required tolerance of .01 % for example.

It definitely sounds like something is going on with the coil but I haven't work on but one Muruyama myself and it was a trimmer with just carburetor problems.

[bgsengine]

But I'm still showing higher than 2M ohm on the meter when testing the primary.

Yes, but again, what are your test points? testing from the wire, directly to the coil armature legs? clean and rust-free? or, what?

[lefty]

I've tried everywhere, armature, mounting screw, block. All clean.

I tested the wire itself and it tests fine. It's just a short length but just to make sure it wasn't broken.

[lefty]

Not sure if this is important but when I tested for spark with my light, I couldn't see the light-up until it started. In other words, 3 or full good pulls with no indication of spark. Then it would fire up and I could see the light. I was inside my garage at the time so there wasn't any light pollution to contend with.

[lefty]

Is there a ballpark for the proper resistance?