How do i get a Tecumseh 5.5HP to idle?

GoldenMotor.com
Jul 5, 2015
128
0
16
Santa Barbara, CA
I picked up an old 5.5hp engine on the side of the road, and it runs great, but it will not idle. I can close the throttle almost all the way and it still wants to go wide open, but then if i close it past a certain point it just dies. I'm wondering if it has something to do with the governor, since i'm effectively bypassing it by manually closing the throttle while the linkage is still attached to the governor arm. This engine is very similar to a Pred 212, so any advice on how to make those idle will apply for my engine too.
Thanks!
 

Agreen

Member
Feb 10, 2013
792
11
18
Southeastern GA
The carb has a main and idle jet. The main jet is responsible for open throttle fuel mixture, and the idle jet (and I'm using the term "jet" loosely) is for when the throttle is shut.

If the engine wants to go higher rpm with the throttle shut, then back the throttle stop screw out a few turns. It's probably keeping the throttle open.

Now, you say you picked it up off the side of the road (good job, btw!) So that probably means it was put there because he couldn't get it running right. But that's fine, because this is an easy fix. The carb needs cleaning. Period. You may need to replace some software inside it, but it needs to be cleaned. Here's what I do. Go get a can of carb cleaner and some clean shop towels. Pinch off or shut off the fuel to the carb. Remove the carburetor. Remove the bowl. It's usually a single bolt on the bottom. See all the gunk inside? Yeah, that's inside the little passages too. Remove the float. Usually it's a little pin you push out and the rest just falls apart. Take note of how it goes together! If needed, take pictures as you do this. The thing attached to the float is what's called the fuel shutoff needle. Its purpose is to stop fuel from entering the bowl when the float goes up. If fuel dribbles out of the carburetor with the engine off, this is the culprit. Sometimes there's a tiny o-ring inside the hole it goes in, and it's called the "seat". It helps seal. Sometimes the needle's tip is rubber and there is no seat (there is, but not a replaceable one). OK, enough of that. There's a brass tube that sticks out the bottom into the bowl. There is probably a flat head slot on it. Remove it with a screwdriver. That's the main jet. There shouldn't be anything else at this point that you really need to remove. So start cleaning. Clean the needle, main jet, everything you can. Spray it down, wipe it off. Shoot carb cleaner through every little hole you can find. It might spray back at your face, so be careful. Clear out those passages with the spray. Make sure you get inside the main jet and needle/seat area, and keep cleaning until you're out of carb cleaner. Use an old toothbrush on hard to get gunk, and a small piece of wire is OK for the main jet, just don't try jamming it in any of the other holes on the carb.

I will say this. If there's a screw that looks like it goes to absolutely nothing, it's probably the idle mix screw. There should be one screw to adjust how far open the throttle is at idle, and maybe one for the idle mixture. If there is one, tighten it in until snug (don't force it, just snug it) and count the number of turns it goes. Then remove it, and clean that hole out! It should shoot carb spray out the front, and inside the carb. If it is only spraying through one hole, block that one off with your finger and give it only one option. That's the important idle circuit you're probably having issues with.

Reassemble it. Make sure you screw the mixture screw all the way in, then count the same number of turns out as you counted in. That ensures the idle mix screw is somewhat close to where it should be. Finish reassembly and fire it up!

Hope that helps some?
 
Jul 5, 2015
128
0
16
Santa Barbara, CA
Thank you for your message! I ended up doing pretty much exactly what you said, i cleaned the carb out well and cleaned all the jets, and there was a dead fly plugging the main jet almost completely, and all manner of gunk in the idle mixture screw hole. After removing those things and cleaning out every little part of the carb i put it back together, pulled the cord, and it idled without a problem! Thank you so much!