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.

You’re going with replacing parts which could work.  It looks like the parts are fine but just taking things apart and putting them back could cure things.  I don’t think they will make a difference. 

 

For reference:

From what’s been posted it seems the block is behind the seat in the area between the seat and the fuel inlet.  Replacing the float and needle won’t affect those.  Removing the seat would.  But that’s a possible problem. 

 

The reason is dealing with the brass insert.

 

On your model the factory puts in the seat and then puts in the brass insert.  The seat shape is a small doughnut over a large doughnut.  The large doughnut part is the size of the needle hole which is also the size of the brass insert OD.  The smaller doughnut is the size of the brass part ID. 

The seat goes in then the brass insert.  The insert covers and holds down the seat large part of the seat.  The smaller part ends up inside the insert. 

 

When you look into the carb needle hole what you see is the brass insert and the small part of the seat. You do not see the full seat which is under the brass insert holding it down.  Removing the seat requires a carb tool with a crochet end.  Using a small probe like can be used for a Tecumseh seat won’t work without damaging the seat.  If you could get it out you can’t insert a new seat as it’s too large without first removing the brass insert. 

 

Removing the brass insert can be a problem.  There’s no lip at the bottom to get a grip on with the carb tool.  Some ways to get the insert out are screw in a screw and pull or tap it put in a machine screw and pull it out or just drill it out.

 

All in all it would be much easier to clear the block behind the seat.  You mentioned the seat may be damaged and if so you have to deal with the brass insert.  If it’s not damaged then you don’t need anything other than to probe and clean the area behind the seat to the carb inlet.

  Just read your update after I posted the above.

  The seats of some carbs can be blown out but I don't think this type of double doghnut with the brass insert could work. 

   I have a few dental tools which are like the Briggs carb tool.  The difference is they have a much sharper point than the blunted carb tool and sometimes rip seats where the carb tool does not.  The Mikuni double doghnut seat is really in there and very difficult to get out without dammaging it - even damaging it without a carb tool because of it being held inplace by the brass insert.

   Not a big deal if your seat is not dammaged as all you need is to clean. 

  

Two kits sold for part 81-5820 which superceeds 81-4700.  So two different needle styles and on kit with no insert but both 81-5820's.

Frank, as a note the jet (main jet) at the bottom of the center carb tube is what I have always seen in the Mukini carbs I've worked on.  It turns out the main jet was moved to the bottom of the emulsion tube in the center of the main tube on your carb.  The hole on your carb is just a hole and smaller than most Mikuni's which fit the main jet. 

The needles on Mikuni's I've replaced have all been rubber tipped needles.  I've never had to pull a rubber seat as they were always good in the carbs I've cleaned.  They are more rugged rubber than in Tecumseh carbs. 

Because of this thread I checked out the carb I posted a picture of above.  It has (had) the rubber seat and brass insert.  With difficulty I did manage to get the seat out with the Briggs carb tool.  I could not get the brass insert out after a few attempts so left it.  I could not get the rubber seat back in after great effort.   I think the only way to get it back in is by removing the insert.  There too much meat to press it back in.  I could not even get it in the hole.  If it could be forced in the chances of it seating the lower lip of the seat is probably impossible.  So, the only way to deal with this carb that I can see is to remove the insert for a seat swap.

I'll take another good look at it later today and see if I can determine exactly what the problem might be. It does not sound or look like it's an easy job to remove the brass insert. Perhaps a chunk of garbage from the old stale fuel is lodged inside there and causing a restriction. It's just so hard to look inside there from either the needle side or the fuel inlet tube.

wow thats a bit pricey for parts.....ok lets take a closer look at the needle and float and how they go together...lm sure the problem is there....when u turn the carb upside the float should drop and sit level with no resistance...then if u turn the carb upright it should drop and sit on the black callaur with no resistance... if thats not happening then your gonna need to figure out why....

first reason l would think is theres dirt and grude in where the needle and seat are... 2 the needle isnt moving freely on the float (the plastic where the needle goes in is pinching the needle to tight) those are the only things l can think it would be.

at this point l wouldnt be to worried about the seat because if that was the problem it most likely would be flooding the engine, not stoping fuel from entering....of cousre make sure its clean at run some water through it to confirm u should easily be able to rule that out.

trouts2 wrote:

trouts and frank

in regards to removing a brass seat....what l usually do is take my tap and die set and tap the brass seat (to whatever size of bolt that will fit) ... then get a bolt and thread it in, put a nut on the bolt first then tighten the bolt up and then tighten the nut up and it usually comes right out. sometimes u need to jig something up to make a space between the seat and nut. l also have a little tiny slide hammer that l sometimes attach to the bolt to remove the seat.....but to be honest l RARELY replace brass seats.

Niper99>>>"slide hammer" - - I like that. OK on tapping.  Probably the over all safest and easiest. 

In the past I was confused about this type of seat.  Looking in there I did not see the usual Tecumseh style of seat I'm used to.  It looked like metal in there almost like the seat was removed and it was a metal to metal fit between the seat and needle or even someone had goofed up and put a metal tipped needle in there inplace of a rubber tipped needle. 

I did get the rubber seat out with the Briggs tool but it was a struggle.  I'll tap it to get the seat out.  Picked up a 40 piece metric tap set the other day for $11.   It paid for itself already on a broken bolt. 

Frank,

   It is possible to get a good view in there to insure you have the needle area clean.  If you shine a flashlight in there with a magnifing glass the area can be viewed.  The brass wall makes a clean 90 with the seat which is flat and has a sharp edged hole in the center.  Normally you'd expect a bevel on the hole but looks like a 90 unless a very minute bevel.   Your's is probably not damaged being well protected by crud. 

I've never had a carb yet that had to have the float needle seat replaced or repaired.   Usually, the float needle would be the source of the problem and even that's a rarity.   Sometimes the float needle would corrode slightly and develop a bit of pitting or a faint recession in the area where it would seat.   Even on 40 year old carburetors it was rare to anything but clean the needle and seat. 

This problem that Frank is having is perplexing to say the least. 

A bit of measurable success to report! I took apart the float and needle and poked and prodded with a paper clip, dental pick and pressed into the seat using an 8 penny nail head (seemed to be about the right size). Hosed it all down from both directions (needle and fuel inlet sides) and reassembled the whole enchilada. I removed the drain screw to ensure a flow of fuel into the bowl (eureka!) and fired her up.

She ran without any assistance from me (i.e. spraying fuel into the throat) for close to a minute. I fired her up again and she ran up and down, high revs then slower revs, kind of elliptical in sound with the higher revs being more prominent. I could get it to even out a bit by gently and sparingly using the primer bulb to feed fuel into the throat. I can't get it to even out and run smoothly unless I use the primer.

This is the most headway I've made in quite some time and feel like a real fix is just within reach -  I needed a little bit of encouragement at this stage of the game. I'm leaning towards the carb being starved of fuel a bit and perhaps a little more attention to the needle seat is required? Any suggestions on where to go from here?

   Congradulations, you're just about there.  What you've described is very good and what I get when I miss some specs.  The varnish in the photos looked lumpy in spots and a brown coating in others which is tough to fully remove from areas you can't directly poke.  More of the same cleaning should get it. 

   It could be the float is off but more likely just some spec's somewhere.   Drain the bowl and check for specs.  If there are then may be just dumping those will work.  

   What did you set the top screw to?  I think it's 1 or 1 1/2 out from gently closed.  You could try backing that out to 2 and see what happens.  If it needs more than that something is wrong.  Actually 2 would indicate somethings wrong but you'd be very close.

  If no specs or the needle adjust does not work then another round of cleaning.  Make sure you have a good flow from the bowl drain.   Focus on the main jet and emulsion tube.  Be gently in the seat area.

ALSO.... Sometimes it takes a few minutes of warmup for it to run smooth but if you're getting wide throbbing then likely dirt.  It could clear by itself with several minutes of running.