Briggs/Nikki Carb Problem

[lefty]

Briggs: 331777-1107 B1 080320z (numbers are pretty tough to read. I cleaned it up the best I could but am not sure about the last couple in the code.
Nikki Carb 594601 (part number from parts site)
Off a tractor but not original to the tractor. Someone put this engine in an old MTD. What a mess.



I got this tractor in that had trouble starting. It needs to be primed with a little gas down the throat to start but once it starts, it's fine. So I took the carb off and noticed a couple of things.

1. The after-fire selenoid plunger is sluggish and the solenoid itself is filled with gas. When I shake it, I can hear it sloshing around in there. I'm guessing there was some sort of o-ring around the plunger shaft but that's long gone if there was.
2. I guess there are two carbs for this engine. The carb I have is the one with the plastic fuel transfer tube body. The float and needle are also plastic. The main jet is a little thing that has an o-ring on it which I guess is supposed to provide enough of a fit to keep it in the end of the plastic tube. But it falls out pretty easily.

Here's a link to the carb info.
http://outdoorpowerinfo.com/repairs/briggs_intek_single_ohv_nikki_carb.asp

I'm guessing the solenoid is junk?
And that main jet, it fell right out of position when I took the carb apart. And when I install it and tip the body upside down, which is the way it rides, it falls out most of the way. Is a new o-ring and/or main jet needed?

Thanks very much.

[KE4AVB]

Yes there is [was] an o-ring that seals solenoid internally. Not replaceable, new solenoid is only choice.

As jet o-ring Briggs don't offer it separately but I pm you a PN of the o-ring that you can get for it.

[bgsengine]

Most of the carbs now seem to be "unified" down to one replacement part number, which I believe is now the Nikki version. Yes your main jet should fit snugly (if you look close the o-ring is probably worn flat or hardened) Solenoid should not get any gas in it , there's no replaceable seals so you need a new solenoid.
However you may want to do a little price shopping and figure your parts and labor for the main jet, solenoid and new bowl gasket as compared to simply replacing the whole carburetor with a new one - you might find the replacement carburetor is a better and more cost-effective repair.. but compared against the worth or value of the whole thing, it may not even be worth fixing the tractor to begin with?

[lefty]

You may be right on both accounts. A new carb appears to be at least $100+ and the machine is a relic. The engine is much newer, or appears so.

Thank you.

[38racing]

Chinese aftermarket might be about $20. I'm trying to decide how to proceed. I have a 31 series with the walbro carb. It's once again got gas in the crankcase even though I use the inline shutoff. I'm wondering if it doing it while running although there's no indication of flooding but I am cutting a side slope with carb side up. I have a needle seat and float already so I'll try that again but was looking at the Nikki style aftermarket. Two canadian sellers on ebay had bad feedback. Someone claimed they are not actually in Canada.

[KE4AVB]

Depend where you put the fuel shutoff if you a vacuum fuel pump. If after the fuel pump you might have a leaky diaphragm in the fuel pump.

Also you have gravity carburetor that is fed by a fuel pump that can be a problem too.

[KE4AVB]

You may be right on both accounts. A new carb appears to be at least $100+ and the machine is a relic. The engine is much newer, or appears so.

Thank you.

Well the engine is a 2008 model if that helps.

[lefty]

I found the model number on the tractor. 1997. So she's a bit older than the engine.

This is my brother's machine. He bought it from a local old timer that does some repair / reselling. He patched this one together. The throttle is backward. It's a pretty good looking machine in my opinion. But it has some other problems as well. The blades are junk and someone torqued the living daylights out of the blade nuts. I managed to get one off and there is no thread left on the spindle shaft. One of them I couldn't even get off with my Ingersoll.

I was wondering, is it ok to heat those nuts or do I need to worry about the bearings up in the spindle. I saw some Stens spindles on amazon for short money but they were getting bad reviews...untapped holes (not necessarily a deal breaker), pullies flying off while mowing and such. I know I need at least one spindle and 3 blades. It's my brother's so it's just going to be parts but it's getting up there.

[bgsengine]

I was wondering, is it ok to heat those nuts or do I need to worry about the bearings up in the spindle..

If you're gonna heat 'em, then cut 'em off with the torch, but as you said - no threads left, so why not just throw new spindles in and have done with it? Also most new replacement spindles (including OEM ones) with aluminum housings, will be untapped holes , self-threading bolts are used to put them on, and most of those bolts designed as one-time use anyway (as in they generally like to break off when trying to remove the bolts after a couple years..)

One other note to the heating idea - if you'd like to try and save the spindles and bearings, you could also drill (stepped up 2-3 times to as wide a hole as possible for the nut) 180 degrees apart just deep enough to maybe nick the spindle threads , then use a cold chisel to split the nut - you won't be heating bearings or shaft and if it's just tight (and not stripped) nuts , chance of saving the threads too, then just need new nuts. Trick is rather more difficult when dealing with flanged nuts like on most newer MTD models since you also need to cut through the flange to split the nut.. might get away with a cut-off wheel (dremel or rotozip, etc) to trim off the flange where you plan to drill the nut...

[lefty]

Splitting them sounds like a good idea. Maybe get away with just replacing one spindle. The nut I was able to get off was not flanged so that's good news.

Thank you.