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Briggs-Fan
Briggs-Fan, Small Engine Technician
Category: Small Engine
Satisfied Customers: 1198
Experience:  over 15 years experience in small engine repair, multiple certifications
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I'm working on an Echo SRM225 weedeater. You t the

Customer Question

I'm working on an Echo SRM225 weedeater. You hit the throttle and it boggs down. I've replaced the carb, fuel line and filter. Still same thing. It idles just fine, so where is my problem? BTW, I just changed the coil, that was it's problem in the first
place.
Submitted: 1 year ago.
Category: Small Engine
Expert:  Curtis B. replied 1 year ago.

Is coil mounted correctly? Can't be upside down, throwing off the timing? Is it gapped at .010 inch?

Customer: replied 1 year ago.
My bad, I'm working on 2 weedeaters. This one I'm talking about now, I did not change the coil. It just boggs down when you hit the throttle.
Expert:  Curtis B. replied 1 year ago.

Ok, how is carburetor? Has t been cleaned, have you tried to adjust the high speed screw?

Customer: replied 1 year ago.
New carb and there no adjusting screws on the carb
Expert:  Curtis B. replied 1 year ago.

Bog down on throttle increase is starving for fuel. Fuel strainer ,hose to carb, and with no adjustment, !!

Customer: replied 1 year ago.
New fuel line and filter. Is there a chance something is in the head?
Expert:  Curtis B. replied 1 year ago.

Exhaust would have to be plugged. I doubt that is problem.

Customer: replied 1 year ago.
Screen is clean, but there is a a honeycomb looking like thing in the muffler. It may be plugged, don't know, can't get it off! Next guess?
Expert:  Curtis B. replied 1 year ago.

Remove the muffler and put on your ear plugs and test with muffler off!

Customer: replied 1 year ago.
Still does not rev up, just boggs. Clutch, or in the head maybe?
Expert:  Curtis B. replied 1 year ago.

Is the output cable and drive free, Then it should not be a clutch problem. And cylinder, would show damage if it were bad. I still think it is lack of fuel!

Customer: replied 1 year ago.
New carb, line and filter!
Expert:  Curtis B. replied 1 year ago.

Fuel lines correct? Where is primer? In carb, or separate.

Customer: replied 1 year ago.
Fuel lines have to be correct or it would not run, right? Primer is mounted to carb
Expert:  Curtis B. replied 1 year ago.

Simple enough to check, remove the lines and press the primer while feeling the lines. The suction has to be the line in tank with the strainer.

Customer: replied 1 year ago.
Lines hooked up right, primer bulb full and it runs, just doesn't rev up when you hit the throttle.
Expert:  Curtis B. replied 1 year ago.

Ok, I will opt out. Maybe someone else will have a better idea.

Customer: replied 1 year ago.
Ok, Thanks for your help
Expert:  JohnF2015 replied 1 year ago.

Can you provide the numbers from the carburetor that you have on this machine? Is it a Walbro, Zama carburetor? It sounds like you have checked everything else, I think that you need to make a fine adjustment on the carburetor in order to get this up and operating properly. If you can provide me with information from the carburetor I will see if I can help you make that adjustment. Is it a rotary valve or throttle plate style carburetor?

Customer: replied 1 year ago.
Hi John,
The carb part number is ***** The carb is a RB-93. It is a rotary valve and I don't see any adjusting on this carb.
Like I told Curtis, it will start and run, it just will not throttle up. Help!!
Expert:  JohnF2015 replied 1 year ago.

If you will look right down at the top center of the rotary valve, Is there a plastic plug inserted into the center of the rotary valve? If so, you can remove the plastic plug and there will be a very tiny flat head adjusting screw there that you can turn to adjust the carburetor. You would want to turn it out about an 1/8 of a turn at at time to see if it helps.

Customer: replied 1 year ago.
OK, I've turned it all the way open and closed, no change, except now I can't get it to idle. With the shaft to my left, engine to the right, turn that screw clockwise til it stops, then back it off how much?
Expert:  JohnF2015 replied 1 year ago.

Normally around 1 1/4 - 1 1/2 turns and the machine should start and run, you may have to fine tune from there.

Customer: replied 1 year ago.
Thanks, ***** ***** for tonight, I have to work Tue and Wens, daughter getting married Sat, so I don't know when I'll get back with you! As Curtis, it may take me a while, but I always rate excellent!!
Expert:  JohnF2015 replied 1 year ago.

Just let me know it there is anything else that I can help you with.

Thank you it has been a pleasure to assist you.

Customer: replied 1 year ago.
I'm back, should be here most of the day. I've turned it out 1 1/2 turns, it will start but not idle, also it still will not rev up. What next?
Expert:  JohnF2015 replied 1 year ago.

I would turn out about another 1/8 of a turn and see if it helps. If not I am going to suggest and air leak in the system somewhere that is causing the engine to not pull enough fuel through to continue to idle or rev up when throttle is pulled. It could be a gasket leak on the crankcase, cylinder base, or crankshaft seals, maybe even carburetor mounting flange gaskets.

Is it easy to get started? Or do you have to pull it a lot to get it started?

Customer: replied 1 year ago.
Choke, pull once, take off choke and it starts. The reason he brought it in was, start it and would not rev up. I did not know that there was that adjusting screw that you told me about, so I just ordered a new carb. Installed it and no change. Currently, it's worse now than it was when he brought it in.
Customer: replied 1 year ago.
I just got off of the phone with an Echo dealer and he thought it may be the spark module. What do you think?
Expert:  JohnF2015 replied 1 year ago.

Not very likely, normally they either work or they don't. You can check it though if you have an inline spark tester, just insert your spark tester and start the machine and watch to see what the spark is doing at idle and upon throttle up.

You've had the exhaust off and checked to make sure that it wasn't blocked or stopped up.

It starts easily enough that one would want to rule out an air leak anywhere. You have made certain that the fuel lines are hooked up properly on the carburetor, fuel lines are not cracked or broken, fuel filter is clean and in good condition.

What happens if you start it and when trying to throttle up you spray a little carburetor cleaner in the throat of the carburetor. Will the machine come up to full rpm and continue to run?

Customer: replied 1 year ago.
Put the tester on it, at idle, the light flashes, rev it up the light gets brighter.Tested it with the exhaust off, no change.Fuel lines have to be hooked up correctly or it would no run, right? New fuel supply line and filter.Spray carb cleaner in the carb, it floods out and dies.What next?
Expert:  JohnF2015 replied 1 year ago.

It is starting to easily to be an air leak issue. The ignition doesn't seem to be a problem, if it were it would quit firing or miss fire when throttled up. I still go back to a fuel starvation issue, there has to be something in that carburetor that is not allowing enough fuel to pass through when throttle is pulled to bring engine up to full speed. Does the new carburetor numbers match the old carburetor numbers exactly or was there a change in the carburetor. This could explain the problem. I would research the carburetor a little more closely to see if the jetting is different or some little something changed on it. You had the same problem with the old carburetor, did you clean and/or rebuild the old carburetor?

Customer: replied 1 year ago.
This unit has 3 lines coming out of the tank. 1 for fuel supply, 1 for return and 1 for vent. What are the chances that the vent is plugged? I've actually pulled the filter off of that end and it just squirted gas all over me!Same problem with the old carb, I just put a new carb oon it!
Customer: replied 1 year ago.
I did pull the coil and cleaned up the contacts, but no change.
Expert:  JohnF2015 replied 1 year ago.

If it were the vent it would at least run good for a while until it could no longer suck any more fuel out of the tank and then it would die.

If the fuel supply line and the primer return line were hooked up at the carburetor wrong it could cause your problem. The primer return only goes into the tank a very short distance and may not stick down into the fuel far enough to get it to run at higher rpm. It should show up though in starting as well since you would not get enough fuel to start easily. I still believe there is something different about the carburetor and maybe the new one will never run properly on this machine. It could be jetted differently, internal passages maybe different enough to cause problem. I would go back and double check to make sure that the carburetor numbers match up and if not then I want to know for sure that it is an exact replacement for the old one that was on there.

Customer: replied 1 year ago.
All right, quit yelling at me!!
This is the numbers off of the old carb; K93 03C RB 19.
New carb, K93 55A RB40.I'm going to change back the carbs, adjust the old one and see what happens.
Back in a flash!!
Expert:  JohnF2015 replied 1 year ago.

Not yelling, just thinking that there is something different about the two carburetors that may be causing your problem. I could be wrong, but with everything else that you have done it just doesn't make sense that it could be anything else.

Customer: replied 1 year ago.
Changed carbs, still same thing. I'm at a loss, this is why I usually call Curtis, but you may be my 2 cycle person to go to, IF you figure this P.O.S. out!! LOLA little background on me. I started a small engine repair shop, as a hobby, 6 years ago. My "hobby" is turning into a business! I do get stumped from time to time and I'm so thankful for you guys helping me out! There are times that I'm so burned out that it is a simple fix, that I've have over looked it, except this time!! It just used to be me working on the neighbors mowers, to I have customers coming from as far as 30 miles away for me to work on their equipment.OK, enough of the BS, HELP!!
Expert:  JohnF2015 replied 1 year ago.

Take a close look near the bottom of the carburetor, in the side. Do you see any holes that may be plugged with a plastic plug, wondering if there is a second adjustment on this carburetor.

Customer: replied 1 year ago.
Looked at the old one, and yes there is. Now what?
Expert:  JohnF2015 replied 1 year ago.

Can you remove the plug that is inserted in there? Once the plug is removed you should find a small flat head adjusting screw that can be turned to adjust carburetor, I would try turning it out just a little bit and see if it makes any difference.

Customer: replied 1 year ago.
I turned it down clock wise to a stop, then backed it off about 1/16th of a turn, sounds better, but still not right. I've tried adjusting both while it's running, still not right! Next suggestion, Big Daddy!!
Expert:  JohnF2015 replied 1 year ago.

Give me a moment to do some digging, I will get back with you here in just a little bit.

Customer: replied 1 year ago.
OK, Bud! I'm done for the day, wedding shit going on!! I'll get back with you soon! Thanks for your help!!
Expert:  JohnF2015 replied 1 year ago.

I am digging back through some of my notes to see if I have any references to this problem on any other machines. I have been doing repairs for almost 30 years so I have a lot of files that I make notes in from time to time when I run into something weird or out of the ordinary. I will let you know what I find here in a little bit.

Customer: replied 1 year ago.
I'm back. The small adjusting screw, underneath the primer bulb is closed and it will idle and run, not right, but run. I can adjust it and nothing happens. I've gone so far as to pull the filter off and still the same.
Expert:  JohnF2015 replied 1 year ago.

Have you checked to make sure that the pulse passage from the crankcase to the carburetor is not obstructed or blocked? This would cause the machine to not want to take fuel or run due to not getting enough fuel to the carburetor to keep it running properly.

Customer: replied 1 year ago.
It's clear. It just sounds like it is starving for fuel. It revs about 1/3 of what it should.
Expert:  JohnF2015 replied 1 year ago.

I agree, it sounds like it is starving for fuel but you have covered everything that could be a possible cause and nothing seems to be a fix for it.

I am going to opt out of your question at this time which will allow for one of the other experts here to look at our conversation and add to it if they have any other suggestions.

I am sorry that I could not be of more help to you on this.

Customer: replied 1 year ago.
Thanks for your help! I'll use you again!
Expert:  Briggs-Fan replied 1 year ago.

Hi my name is ***** ***** well and welcome to Just Answer. . I was wondering if you removed the muffler and checked the muffler and screen to see if it's clogged . That will create back pressure and could cause it to bog down

Customer: replied 1 year ago.
Hi John, here is the story from the beginning! Customer brings in the weed eater and it's only running at half speed, acting like it's choking out. I replace the carb, fuel line and filter. I pull the plug, it has good spark and compression. I take the muffler off, run the machine with no change. JohnF2015, told me how to adjust the carb, (I didn't know there was any adjust on this carb, thus I bought a new one.) Currently, I can get it to run about 1/3 of what it should.To me, it acts like something is in the head or binding in the clutch. It's just not running right, or I would tell the customer just to pick it up. You know that bad news spreads faster than good news, so I have to make this thing right! Any ideas? BTW, I've spent a shit load of hours on this thing, (but I won't charge him for) just want it out of the shop!!I have another job that I'll work at till noon tomorrow, then it's back to this machine!Thanks for your help
Expert:  Briggs-Fan replied 1 year ago.

Have you checked the muffler and screen to see if they are clogged ?

Customer: replied 1 year ago.
I have ran it without the muffler on and no change.
Expert:  Briggs-Fan replied 1 year ago.

So at this point will it start and ideas or no

Customer: replied 1 year ago.
Sorry it so long to get back with you, I've been down in the back for a few days.
It will start, idle and run with or without the muffler. It will only rev up about 1/3 the way it should, with or with out the muffler.
Expert:  Briggs-Fan replied 1 year ago.

Ok have you separated the engine from the shaft and ran it to see if something is binding ?

Customer: replied 1 year ago.
No, but I'll do that tomorrow. I'm hurting right now, hope the pain meds kick in!!
Expert:  Briggs-Fan replied 1 year ago.

Ohhh man , hope you feel better .

Expert:  Briggs-Fan replied 1 year ago.

Hi , hope your feeling g better , we're you ever able to separate the engine from the shaft to see if it was something in the shaft ?

Expert:  Briggs-Fan replied 1 year ago.

Hi , hope your Thanksgiving was good did you ever get a chance to unhook the shaft from the engine and see if that was what was the problem