Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

It's in decent condition, new rubber impeller, scraper bar and overall good shape. The guy I bought it from said it had been professionally serviced 2 years ago but had seen little use since then as he decided to hire a plow guy to do his average residential driveway. I could not get it to start after adding some fresh fuel that I brought with me so I offered him $ 40.00 and said OK. - he had it listed for $ 75.00 on CL. I'm pretty sure he left some old, unstabilized fuel in there and it turned into varnish.

I removed the top and back covers and dropped the fuel bowl. It looked like a bad batch of applesauce in there so I cleaned it out and shot the carb with carb cleaner and reinstalled the bowl. It fired up for a few seconds and then died. A good carb cleaning appears to be in order and I'm wondering if I can do this with the carb installed or is it easier/better to remove it from the engine (Suzuki 47P)? I've never removed a carb before but am mechanically inclined and would like to get this operational for next winter.

I remember Borat discussing a cleaning of the jets using wires to remove any build up inside that could cause fuel starvation. I have never done this so any suggestions or tips will be very much appreciated.

If  the issue is not getting fuel into the float bowl, there must be an obstruction in the float seat.   With the float in the down position, the needle must follow and fuel should flow.   Performing the above test with a piece of hose and water will confirm the float and needle effectiveness.  If he get's good flow into the float bowl, the only thing left is obstruction in the venturi orifices, main/pilot jet and/or gallery obstruction, emulsion tube obstruction. 

 I wish I had that carb in my hands.  I really enjoy working on carbs.    

To a person with limited carburetor maintenance experience such as Frank, there is a huge learning curve.  Hats off for him having the ambition and courage to roll up his sleeves and get at it. 

I'm  waiting for a replacement reed plate and carb for one of the old Lawn Boys I recently bought.  When I get the reed plate, I plan on experimenting with a suitably sized carburetor off of a 1964 Mercury 3.9 h.p. outboard motor.   I want to see if it will fit and work on the mower.   

I had an initial brain wave to put the power head from the outboard  on the mower.  Then the liquid cooling issue arose which would require a a radiator and a pump etc.....   Not going to happen.  The carb experiment will have to do.

Below are the ports on the manifold side of a Mikuni.  The collar on this one was stuck like most but comes right off with light tapping.  The tab on the collar prevents the float from going too low which would allow the needle to fall out.

That is one grimy carb Trouts. 

Looks like it's been subjected to a fair amount of corrosion probably from salt.  That baby has to come completely apart including the butterfly valve if you can get it out without breaking the little screw that's holding it in.  It looks pretty rusted.   

the fuel level in the carb must sit high enough that the emolsion tube sits in the fuel.. if not it will not run.

lm worried that the float is pinching the needle to tight and its not moving freely....or maybe its just full of junk where the needle and seat is?.

now IF the float was moving freely the engine would run on full throttle only..EVEN if every other orfices was plugged in the carb.....and we know that becase when frank sprays fuel into the throat of the carb its stays running....so if the MAIN JET isnt plugged (which frank says its clean) then that would CONFIRM that the fuel level in the carb isnt correct...and the only thing that controls fuel level is the the FLOAT & NEEDLE opeartion.

"then that would CONFIRM that the fuel level in the carb isnt correct...and the only thing that controls fuel level is the the FLOAT & NEEDLE opeartion."

Makes sense. 

That's why he should do a test with a piece of hose full of water attached to the fuel inlet to see if the float is operating correctly.   With the very slightest amount of upward pressure, it should seat the float needle.  Release the float and it should just drop allowing the water to flow down past the float needle. 

I agree that the engine should run at speed off of just the main jet.  If he can get the engine to run by injecting fuel into the venturi, and it doesn't run on it's own, there's probably no fuel in the float bowl. 

Got to wonder what's going on with this carb.  From the pictures, it looks like it should go.  However, we have not seen the needle seat. 

trouts, borat, nipper: I can't thank you guys enough for your guidance and insight with this project. The beers are on me when we finally get this finished! 

I had a busy day so I was not able to spend too much time on this today but here's where I'm at so far. I was able to remove (and not damage) the black plastic collar on the main jet tube - it was pretty nasty under there. I then removed the float and gave both areas a thorough cleaning. Pressed the seat inside where the needle sits but I think it needs to be replaced as it did not make too much of a difference from the first time I pressed it inward. The float when reinstalled still does not sit level no matter how much or hard I try to press the needle inward.

I also removed the black chunky gasket type component on the manifold end and was finally able to see and access the 3 mysterious holes that were eluding me. I gave them all a good dose of the bag tie wire and hosed everything down with copious amounts of carb cleaner. I reinstalled everything and got ready to fire her up!

Unfortunately, she would only stay running as long as I kept spraying fuel directly into the throat. VERY frustrating!!!! I can keep her going indefinitely if I'm spraying fuel in the throat.

What do you guys think - replace the needle seat and see what that does? I lost the little spring but as trouts stated and I agree, I don't think it makes much of a difference. The float seems to be restricted in terms of movement. It does not have a whole lot of free play and still feels kind of spring loaded which is why I'm thinking I should replace the seat and see what that does. To be honest, I'm almost thinking of replacing the carb completely but I've gone this far so replacing a few parts in hopes of getting this resolved is an acceptable option. I'd like to keep it original if at all possible.

On the bright side, we've got about another 7 months or so to get this problem resolved and I've gained a ton of experience!

Once again, I thank you guys for all your help.

Frank

if it was me frank l would replace the needle & seat and float just for peace of mind at this point.

What is the factory model number of your machine?  

When put back together, drain through the bowl to see if you get a decent flow.

You can keep it running by squirting in gas but can you now prime it to keep it running?

You should be able to prime many times and get gas in the throat.  If not and you have no air leaks which you don't then something is fuzzy in the needle area.

Is there a jet at the base of the center tube by the cutout part of the black collar?  It would be a small screw-in part.  That should be there and very clean.

I would verify float operation in a glass before I bought anything.   Also in the sink, put a small length of gas line on and fill the line with water when the blow is held up with your finger.  It should hold the water and when you drop the bowl flow freely.  Does that flow look about that you get when you drain with the gas drain on the bottom of the carb bowl?  It should be close.  You should be able to lift the carb up to let the float drop and get flow.  After putting the carb back into the water flow should stop.  The needle should never stick and what you want to look for.

When sitting in the glass on the glass rim you should be able to leave it for an hour with no leak. 

trouts: Model number is 38430, s/n  is 7908851. This indicates a 1997 date of manufacture.

The prmer bulb works mechanically, but will not provide fuel to the carb as it should. It is brand new as the original was missing so I bought and installed a new one. Not sure why the primer does not work as it should. The engine will stay running as long as I continue to spray fuel directly into the carb throat.

Look at the previously posted pictures of the carb tube base - I do not see any type of jet on or near the black plastic collar. The only one is located inside the tube and can be remove by backing it out like a screw. That is very clean and the orifices are open.

I'm going to replace the needle, needle seat and float as suggested by nipper and see if that cures the problem. It seems as though the fuel cannot get past these areas to feed the carb and keep her running. It's hard to see into the needle seat but it looks like the rubber is damaged in one area which may be causing the fuel feed problems. I assume that the cost of these parts is much less expensive than replacing the whole carb (+/- $100.00) so I'll take a chance and see what happens.

Question - how do I remove the seat without damaging the carb? It appears to be made of brass and rubber and is pressed into the hole where it belongs. Do I try and grap it with needle nose pliers or use a screw inserted into the opening and pull it out that way? Just not sure what is the best way to remove this so I can replace it.

Any other suggestions or thoughts are very welcome.

"The prmer bulb works mechanically, but will not provide fuel to the carb as it should." That's an awful big coincidence. Too big. I would find out why that's not working before doing anything else, it could very well be another symptom of why your carb isn't getting fuel.