BR550 Issues

[Roger]

View attachment 91179

Whoa. That kills that idea. I'm going to measure mine again tonight. Maybe I managed to screw up this simple measurement. If not, it's impossible to understand why two coils that should be identical yield such wildly different results. And for that matter, how mine is running at all. Thanks again for your help.

 

[Roger]

Whoa. That kills that idea. I'm going to measure mine again tonight. Maybe I managed to screw up this simple measurement. If not, it's impossible to understand why two coils that should be identical yield such wildly different results. And for that matter, how mine is running at all. Thanks again for your help.

Before I leave this completely, I assume that the red lead is connected to the red input of the meter and the black to the black? Sorry, but can't see from the pic.

 

[Lone Wolf]

Before I leave this completely, I assume that the red lead is connected to the red input of the meter and the black to the black? Sorry, but can't see from the pic.

Yes they are properly connected.

 

[Lone Wolf]

Whoa. That kills that idea. I'm going to measure mine again tonight. Maybe I managed to screw up this simple measurement. If not, it's impossible to understand why two coils that should be identical yield such wildly different results. And for that matter, how mine is running at all. Thanks again for your help.

Well if all things are equal the coil is bad, are all things equal did you test it just like I did? Mine is a BR600 which supposedly uses the same coil ,we have different meters, mine only has one scale for ohms . Not being an electrician or technician I would ask the guys on here that are what they think?

 

[Lone Wolf]

Whoa. That kills that idea. I'm going to measure mine again tonight. Maybe I managed to screw up this simple measurement. If not, it's impossible to understand why two coils that should be identical yield such wildly different results. And for that matter, how mine is running at all. Thanks again for your help.

I did it with the two wires of and cool engine.

 

[breese]

Not being an electrician or technician I would ask the guys on here that are what they think?

Did you both check / replace the battery in the meter?
I have been down that road on a generator I thought the regulator was bad when the meter read the 220V at 160V

 

[Marshy]

Yes, some do to mitigate EMI. However, 2 MΩ is way too high for that application.

Yes but they do occasionally go bad.

 

[Roger]

Well if all things are equal the coil is bad, are all things equal did you test it just like I did? Mine is a BR600 which supposedly uses the same coil ,we have different meters, mine only has one scale for ohms . Not being an electrician or technician I would ask the guys on here that are what they think?

Made the measurement again...20.3 kΩ. Same as yesterday. The measurement is the same regardless of lead polarity, and I verified that my meter is accurate with a known 100 kΩ resistor.

This is a BR550, but I've verified that it uses the same coil as your BR600. I think that given your measurement versus mine, and assuming that your meter is good, there's nothing to conclude other than my coil is bad --- I mean REALLY bad. I'd love to know what's inside that thing that could fail in such a way. Anyway, I'm planning to purchase a new coil. It's a minimal investment. I'm going to run this thing tomorrow and hope for the best. I'll let you guys know what happens.

You guys are great, especially Wolf. Sorry to pull you through a hole like this. Perhaps when it's all said and done we would have all learned something new about how to troubleshoot Stihl blowers.

Thanks again, all.

 

[Lone Wolf]

Made the measurement again...20.3 kΩ. Same as yesterday. The measurement is the same regardless of lead polarity, and I verified that my meter is accurate with a known 100 kΩ resistor.

This is a BR550, but I've verified that it uses the same coil as your BR600. I think that given your measurement versus mine, and assuming that your meter is good, there's nothing to conclude other than my coil is bad --- I mean REALLY bad. I'd love to know what's inside that thing that could fail in such a way. Anyway, I'm planning to purchase a new coil. It's a minimal investment. I'm going to run this thing tomorrow and hope for the best. I'll let you guys know what happens.

You guys are great, especially Wolf. Sorry to pull you through a hole like this. Perhaps when it's all said and done we would have all learned something new about how to troubleshoot Stihl blowers.

Thanks again, all.

Good luck my friend and keep us tuned in.

 

[Roger]

Update. No replies necessary or expected.

I went out this morning and bought myself a brand new NGK plug to begin today's festivities and to satisfy breese's observation. Installed it, and after two pulls the engine springs to life, runs for a minute or two, and then dies. Pull, pull, pull, pull...nothing. Dead. Yank the new plug: bone dry. Open the fuel tank cap. Pull, pull, pull...nothing. Spray 2-cycle down the carb throat, engine roars to life and runs for another minute or two, and dies.

In short, I'm right back where I was eight weeks ago. For those who haven't followed this drama, this is after new fuel lines, filter, carb rebuild, carb replacement, and valve adjustment. And I don't care what Wolf's ohmmeter shows, this is a fuel problem.

Can you say "despondent?" I can. I'm standing in the driveway looking at my dead BR 550, thinking. Then he came. You know, that other guy in your head. The one who shows up at your weakest moments to make you believe without reservation or hesitation that you can't think your way out of a five sided box. Yeah, THAT guy.

Hey, Dummy.

What?

Dummy, what's been the cornerstone of all your efforts these past eight weeks? You know, the one symptom that led you down this tortuous eight-week path?

The engine won't start, and the plug is dry. Therefore, I have a fuel delivery problem, not an ignition problem. I've known this classic diagnostic since working on minibikes when I was 10 yrs old.

Hey, Dummy, have you ever seen a wet plug in this thing?

No.

Hey Dummy, is there something you can do that, according to your logic, would force the plug to be wet?

Well, yeah. I pulled the plug wire and cranked the engine about a dozen times. Pulled the plug. Bone dry. Reassembled everything and the engine starts after two pulls.

Hey, Dummy, what does that tell you?

Well, for reasons known only to God and Stihl, the classic wet/dry plug diagnosis may not apply to this engine.

Right, Dummy. What are we gonna do now?

We're gonna order a new coil.

Good boy, Dummy.

 

[Lone Wolf]

Update. No replies necessary or expected.

I went out this morning and bought myself a brand new NGK plug to begin today's festivities and to satisfy breese's observation. Installed it, and after two pulls the engine springs to life, runs for a minute or two, and then dies. Pull, pull, pull, pull...nothing. Dead. Yank the new plug: bone dry. Open the fuel tank cap. Pull, pull, pull...nothing. Spray 2-cycle down the carb throat, engine roars to life and runs for another minute or two, and dies.

In short, I'm right back where I was eight weeks ago. For those who haven't followed this drama, this is after new fuel lines, filter, carb rebuild, carb replacement, and valve adjustment. And I don't care what Wolf's ohmmeter shows, this is a fuel problem.

Can you say "despondent?" I can. I'm standing in the driveway looking at my dead BR 550, thinking. Then he came. You know, that other guy in your head. The one who shows up at your weakest moments to make you believe without reservation or hesitation that you can't think your way out of a five sided box. Yeah, THAT guy.

Hey, Dummy.

What?

Dummy, what's been the cornerstone of all your efforts these past eight weeks? You know, the one symptom that led you down this tortuous eight-week path?

The engine won't start, and the plug is dry. Therefore, I have a fuel delivery problem, not an ignition problem. I've known this classic diagnostic since working on minibikes when I was 10 yrs old.

Hey, Dummy, have you ever seen a wet plug in this thing?

No.

Hey Dummy, is there something you can do that, according to your logic, would force the plug to be wet?

Well, yeah. I pulled the plug wire and cranked the engine about a dozen times. Pulled the plug. Bone dry. Reassembled everything and the engine starts after two pulls.

Hey, Dummy, what does that tell you?

Well, for reasons known only to God and Stihl, the classic wet/dry plug diagnosis may not apply to this engine.

Right, Dummy. What are we gonna do now?

We're gonna order a new coil.

Good boy, Dummy.

Was the carb replacement OEM Stihl? If it was not that may be the problem if it was OEM I would Vacuum and pressure test the blower before ordering a coil. And I assume the gas mix is fresh not months old right?

 

[Roger]

Was the carb replacement OEM Stihl? If it was not that may be the problem if it was OEM I would Vacuum and pressure test the blower before ordering a coil. And I assume the gas mix is fresh not months old right?

The new carb is not OEM, but it now acts that same way as the original. I contemplated a leak-down test weeks ago, but I don't have the fixtures and other equipment to do it. And I'm reasoning that if I have a leaky crankcase or rings, the thing is junk anyway. I can't fix that myself, and the cost to have someone do it would be prohibitive. So, the new coil is my last hurrah. If that doesn't work, I'll throw the original carb back on as a final effort. If that fails, I'll buy a new blower. And the gas is fresh, 50:1, alcohol-free premix. I'm near at the end of the line. Either way, it'll be a relief to get this behind me with a fix or a new machine. I'm hoping for the former, and hanging my hat for now on the huge difference between your coil resistance measurement versus mine.

 

[Lone Wolf]

The new carb is not OEM, but it now acts that same way as the original. I contemplated a leak-down test weeks ago, but I don't have the fixtures and other equipment to do it. And I'm reasoning that if I have a leaky crankcase or rings, the thing is junk anyway. I can't fix that myself, and the cost to have someone do it would be prohibitive. So, the new coil is my last hurrah. If that doesn't work, I'll throw the original carb back on as a final effort. If that fails, I'll buy a new blower. And the gas is fresh, 50:1, alcohol-free premix. I'm near at the end of the line. Either way, it'll be a relief to get this behind me with a fix or a new machine. I'm hoping for the former, and hanging my hat for now on the huge difference between your coil resistance measurement versus mine.

Send it to me and I will test the Vac and pressure for you free your cost just shipping . As a last resort after you try the coil. I have a lot of doubt about aftermarket carbs. Also tell me how you adjusted the valve clearance?

 

[backhoelover]

Send it to me and I will test the Vac and pressure for you free your cost just shipping . As a last resort after you try the coil. I have a lot of doubt about aftermarket carbs. Also tell me how you adjusted the valve clearance?

+1

 

[backhoelover]

have we ruled out a pin hole in the fuel line. the fuel line on the br 4 mix saw is the longest fuel that i know of. when you did a leak down test was the blower at operating temp? i have seen them pass a leakdown test cool but as soon a the blower come up to operating temp would have all kinds of leak by on the rings. i have also seen where the valve seat was pinged up pretty bad to where they would run funky too. also a wore down cam will cause a over heating and the will run like its starving for fuel

 

[Roger]

Send it to me and I will test the Vac and pressure for you free your cost just shipping . As a last resort after you try the coil. I have a lot of doubt about aftermarket carbs. Also tell me how you adjusted the valve clearance?

Wolf, that's a generous offer and I appreciate it. In fact, after my initial post on this forum I didn't expect any responses. What I got was a bunch of guys who are as invested in making this thing run as me. Been a great experience regardless of how it turns out. My plan is to make this final push to get it running. If it fails I'll buy a new one and maybe keep this thing around as a project. If I can resurrect it at some point I'll sell it. It's a great machine with a great name...when works.

I bought the valve clearance kit and set the valves as described in the Stihl maintenance manual. They were a little lose, but not much. Took my time and pretty sure I got it right. At least it doesn't run any worse than before. Ha!

Backhoelover, all the fuel lines have been replaced. No sign of leaks anywhere. I never did do a leak-down test -- outside my pay grade. And very hard to believe that I have something drastically wrong mechanically. The blower is 11 years old, but I don't have more than 100 hrs or so on it, and its been babied its whole life -- used only residentially and even spends winters in my basement.

 

[Stump Shot]

At this point, I would be very surprised if you replace the coil and it still acts the same from what you have said. Seen many a small engine with the "Ghost" spark.

 

[Lone Wolf]

At this point, I would be very surprised if you replace the coil and it still acts the same from what you have said. Seen many a small engine with the "Ghost" spark.

That aftermarket carb worries me . If he is reading the OHMS right it is the coil my Fluke was on auto. I am no expert on that stuff and wish an electrician would weigh in.

 

[Stump Shot]

That aftermarket carb worries me . If he is reading the OHMS right it is the coil my Fluke was on auto. I am no expert on that stuff and wish an electrician would weigh in.

The white colored spark pretty much told the tale...

 

[Lone Wolf]

The white colored spark pretty much told the tale...

Maybe, I suppose we will soon know. The fact that the new carb and a rebuild one did nothing may point to the coil but I would vac check it first.