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Ok, I'm stumped. I picked up a Craftsman GTV 16 garden tractor with a Briggs engine (model 402417) to restore. I believe it's an 81 based on the code. The previous owner told me that it would not run unless the choke was fully open. I overhauled the carb and it was nasty (I can't believe it could even run like that) but I cleaned and inspected it properly and reset the jets to the proper baseline setting. Installed it and it did just what he said, it runs real good with the choke on all the way but start to reduce the choke at all and it just flat dies. Any ideas would be appreciated.

Thanks

If you are 100% sure about the cleaning of the carb, then check the seal's (gaskets) between carb and engine. working on full choke, its having too much air/fuel mixture.

When you cleaned the carb, if you did not replace the float needle and pump diaphragm, that would probably be your problem.

In his own words..."I overhauled the carb" so surely he did...but then...!

Then the float level may be set too low. I never know what overhaul or cleaned on this forum means.

I should have specified that I normally would replace all of the gaskets, FP diaphram, needle and seat, o-ring, etc, however as filthy as the carb was, all of the gaskets, etc. looked like they had just been put in. I can't imagine how someone could install those without cleaning the carb but he must have done so. The needle and seat did not look new but I looked it over with a magnifying glass and it still looked perfect. I will go back in and replace all of those just to be sure. Thanks

I am assuming that it has normal hi/lo mixture screws, and not a shutoff solenoid. What happens if you richen up the mixture
settings, does this make it better? Say start at an extra 1/2 turn ccw on each screw? Move that way in 1/2 turn increments
and detail any changes you observe.

The part of working on these that usually gets put back together wrong is the fuel pump.

I'll try adjusting the mixture screws first before I pull the carb again. Thanks

Kcsguide said:

I'll try adjusting the mixture screws first before I pull the carb again. Thanks

Click to expand...

Did you not preset the mix/screws after the overhauling of the carburetor..?

Yes, I set both at 1.5 turns out.

Kcsguide said:

Yes, I set both at 1.5 turns out.

Click to expand...

OK thats fine..:thumbsup:

Viton tip float needle can look great, but it will swell and shut off the fuel to early, producing a lean fuel mixture that adjustments will not solve.

I've ordered a carb/fuel pump kit and when it arrives I'm going to replace everything just to be sure.

You haven't even tried to adjust it? Just curious.

Rivets said:

Viton tip float needle can look great, but it will swell and shut off the fuel to early, producing a lean fuel mixture that adjustments will not solve.

Click to expand...

I am sure that there is a reason that they are called "adjustment" screws......

By the way "Lawnpro", is a viton tip needle the one with the rubber tip? If so, yes, mine has that type. Ok, here is what I just did. I started it up and noticed that it would not throttle down. The governor lever assembly was mounted wrong and was not letting the throttle idle. I removed it and installed it properly then started it up and was able to push the choke off completely and it kept running at idle just fine, however, as I push the throttle up, it will increase to what I am guessing is about half throttle and then it dies. When it dies, the carb sounds like something just opened up and air is either being sucked in or out of the carb? I adjusted both screws out (ccw) a half turn at a time until they were both out 5 turns. No improvement. Then I went back to the 1.5 turn baseline and did the same thing but leaning it out (cw) and still no change till I got to only a half turn out and it died. Seems like the only option left is to put all new parts in when I receive the carb kit. What do you guys think?

I'm sorry, I see now that your handle is "Rivits", not lawnpro.

Error


Just take out number #117 first, and clean out the hole real good with a piece of wire and install.....

It is easy to do and free to try......

It says error, but the link to the parts blowup still works....

let's try it this way..

I pulled out the needle valve (117) and stuck a wire in to clean it out and reinstalled and the results were the same. But that's what I expected because when i cleaned the carb I cleaned it, then soaked it in carb cleaner, then blew out every orofice with compressed air and used a wire as well, so I doubt there is a speck of anything left in it. It also has a brand new inline fuel filter installed. But thanks for the suggestion.

Kcsguide said:

I pulled out the needle valve (117) and stuck a wire in to clean it out and reinstalled and the results were the same. But that's what I expected because when i cleaned the carb I cleaned it, then soaked it in carb cleaner, then blew out every orofice with compressed air and used a wire as well, so I doubt there is a speck of anything left in it. It also has a brand new inline fuel filter installed. But thanks for the suggestion.

Click to expand...

How did you "pull" it out?

I unscrewed it (ccw)

Sorry I took so long to update this but I received and installed the carb kit and ended up with the same results. Then I adjusted both adjustment screws, testing each setting as before with the same results. The only thing that I did not replace was the metal seat (needle and seat). So after the above experimentation I went back in to replace it. The instructions said to tap the old seat, thread a screw into it and pull it out. I could not get it to budge. I hadn't dinged up the seat, just the sides when I threaded it and the needle still moves freely so I put it back together and reinstalled it and ended up with the same results. And since you're wondering, yes, I am positive that the fuel pump is put together properly and now has all new diaphrams, gaskets, springs, etc. I have tried adjusting the tang on the float that pushes the needle up into the seat slightly both ways, again with the same results. They won't sell just the upper carb body, they say you have to buy the whole carb at $155 bucks! I don't think so... Anyone have any better ideas on how to remove the old seat?

Still scratching my head on this one!

Ok, I was able to remove the old seat and installed the new one. I referenced a shop manual that said to adjust the tang on the float so that the float is level with the carb body when held upside down. I did that and then reinstalled it on the tractor. Same results! When I advance the throttle to the point where it starts to die, if I pull on the choke, it will keep running. A choke increases the vacume which sucks in more fuel so I'm thinking that it's not getting enough fuel and I again tried backing out the needle valve a half turn at a time till it was 6 turns out and wouldn't run anymore. I did replace the inline fuel filter with one that is physically smaller than the previous one. Is it possible that it is restricting the fuel flow? Any ideas?

Update, today I removed all of the fuel lines and fittings. They were partially blocked. After using an air compressor and a garden hose, then the compressor again, I got them completely cleaned out. The fitting at the bottom of the fuel tank was pretty bad but I replaced it. It started up instantly! It had been hard to start before. But, when I advanced the throttle, it tried to die just like before. I adjusted the screws like before but got the same results. I also drained the tank and put in fresh fuel. I guess I'll go back and start over from the beginning.

What about the jet that required the allen head wrench, what size wrench was it?

Hold the phone! I never ran across one like that. Do you know where it is suppose to be? I didn't see it on the parts diagram for the carb. I'll go take a closer look. Thanks for the heads up.

Ok, problem is solved. I removed the carb and completely disassembled it again. As I again ran a wire through every port and blew them out with compressed air, I removed the needle valve, (high speed air screw) and looked in the hole with a flashlight, there was no hole! I don't know how I missed it the first two times but it was so packed with dirt that I had to work it with a wire for quite a while before I broke through. I finished cleaning it out, reassembled it, installed it on the tractor and it now runs fine. Thanks to everyone who offered suggestions and advice.