10hp Briggs dies quickly or under load

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  #1  
Old 02-14-14, 06:51 AM
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10hp Briggs dies quickly or under load

Hey there. So I'm sitting here snowed in and thinking about my generator that won't stay running. I've already done a good bit of work and thought I had it solved but the issue came back.

Bought the unit used a couple days back anticipating the ice so I could run my well if the power went out. The unit is a Coleman powermate 5000 and I don't havea manual. It had been left to sit in the past and pprevious owner had been in the carb. At this point it would start and when choked it would run but not without choke so I thought fuel delivery.

Pulled carb and cleaned it up well. A little trash but not a ton. Made sure all passages were clear. Put back together and it would sometimes run with the air cleaner off. It would run a minute or two then die (no choke) so I checked the flow of fuel from the tank and replaced the filter so all clear now.

So important question here. I bypassed the fuel pump thing at this point. Do I really need that thing? It uses crankcase pulses to produce a reciprocal motion and pump. I plugged the crankcase and put it aside. I did test it with the suction in fuel and using my mouth to pulse. It seems to work fine.

After Bypassing the pump and making sure fuel is flowing it ran under 3000w load no issue for fifteen minutes so I thought I was done. Put the air cleaner back on and it wants to die unless choked again.

Spark plug isn't new but is relatively new maybe a year old so I'll get one of those soon too. Looked like the mixture was about normal from the coloring but I'm not sure how much or how often it's been run. Oil is needs Changing but is at proper level. Gas is all new. Low oil cutout switch is disconnected and so is kill switch.

Vacuum leak maybe? There is only one adjustment on the carb aside from the linkage idle screw. I do not know what the screw in the carb body is for but it seems to make no difference. Not sure how to adjust that either...
 
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Old 02-14-14, 06:55 AM
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Thanks in advance for any help by the way. I'm a bit frustrated but these forums have already been a great resource...
 
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Old 02-14-14, 12:28 PM
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Can you post the model and type code off the engine? It'll help narrow down the engine/carb you have.
 
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Old 02-14-14, 06:52 PM
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Definitely. The coleman model is pm0545202.01 and the serial is 74051153. I was not able to find a manual online though I found similar model manuals...

I am not with the machine at present but tomorrow morning I'll post the engine data. I have a picture of the tag but it doesn't have the resolution to read unfortunately...
 
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Old 02-14-14, 06:56 PM
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And thanks. I'm at a loss here. I'll try pulling the manifold from the head and checking that gasket soon. It's a torx and not easy to get at... Should be able to get it done this weekend. I'm renovating my first house and trying to get the painting finished to lay carpet so my schedule is a bit erratic at present...
 
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Old 02-14-14, 10:23 PM
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Something is still plugged int he carb. Take a fine wire and pass it through the passages and blow it out with compressed air. The adjustment screw you are referring to will only make a noticeable difference at idle. It's the idle air/fuel mixture screw.
 
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Old 02-15-14, 07:00 AM
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It's possible that there was some more "junk" that worked it's way into the carb, especially if it had been sitting. Fuel line breaks down after a while too. Flush out the fuel lines, just run some gas through them into a container.

Did you remove the nozzle to clean it or just spray it? A piece of wire, from a wire brush, will work to clean the nozzle.

Is the float moving freely?
 
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Old 02-16-14, 04:15 PM
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Crazy busy last couple days but getting a ton done! Anyway the engine I'dnumbers are as follows. MModel 19e412 type 0107 01 code 960315yd.

As far as the cleaning I'll strip it back down and leave it in Chem dip for a few hours this time before cleaning it. I poked to the extent possible in all the holes with a stainless thread then blew carb cleaner through each hole before using compressed air to blow again. Nothing seemed restricted but it's definitely worth another check.

Fuel lines and the filter all replaced. The bushing that holds the petcock valve in the bottom of the tank shows its age so when I get the bushing I'll really clean the tank as much as I can too. Fuel flows freely through the line and is clean and clear in appearance. I need to pull the bowl and watch the flow through the float passage but yes it moves freely and the rubber tip is in good condition as is the little spring plunger on the other end.

Which passage specifically do you think may be clogged or could it be any?

Also what is the point of the little pump assembly? Shouldn't gravity be sufficient? Don't wanna second guess the design engineers but it doesn't seem to increase the rate of flow through the filter when running. I still am wary of fuel flow issues...

I'll drop the bowl and watch the flow rate tomorrow.
 
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Old 02-16-14, 04:19 PM
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I've also not really perceived an idle per say. When started it runs at one speed. When load is applied the governor pushes the throttle plate and seems to maintain speed. Is it supposed to idle down lower? I've never had a generator like this in the little cage - I've had several welder generators that idle down then step up under load...

Also I did clean what I've called then main jet on motorcycles. It's the hole at the bottom of the emulsion tube right? I removed the main jet / emulsion tube and made sure it was totally clear.
 
  #10  
Old 02-16-14, 06:10 PM
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Disassembly, Cleaning and Repair of Walbro LMT Carburetor used on Briggs and Stratton Engines

So this is the carb I have. Mine is the earlier version without the solenoid on the bowl.

I cleaned it as the author of the page described. I did not replace any parts thoughas the pprevious owner replaced the needle and gaskets. I believe him as they do not look old and the carb had very little trash in it when I first opened it up.

I think I may be have the idle mixture screw too far Open... I also did not remove the plug covering the back of the little idle holes in the throat bore...

Hopefully this description yields some interesting ideas! I'm thinking maybe vacuum leak again... Would I stalling the air cleaner increase manifold vacuum? Also considering the previous owner rebuilt the carb - then sold it - maybe that points to something more extreme like valves or vacuum leaking?

I have done clearances on valves before but do not know the diagnostic aspects... I'll keep reading whatever Google yields me for now!
 
  #11  
Old 02-19-14, 06:18 AM
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Any additional ideas? Short of buying an ultrasonic or drilling out that plug I'm not sure what to do at this point...
 
  #12  
Old 02-19-14, 07:10 AM
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I can't find a users manual for the generator, just a parts manual. It's unlikely that your generator has an autothrottle. Many small generators don't. They just run at a governed rpm (about 3600 rpm) all the time, load or no load.

If it ran under load for 15 minutes then it should be in fairly good mechanical condition. Small engine carbs can be very difficult to clean. Did you remove the main jet and clean it?

Manifold vacuum is dependent upon several factors such as throttle plate position. Installing the air cleaner should cause the engine to run slightly richer or the same as closing off the choke some. How is the filter?

Not using the fuel pump, on a carb set up for a fuel pump, can cause you to run lean (need choke).
 
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