1972 Scout 2 out of wack

[stephenjimenez]

Alright. So its running now. Thank the lord and all my good buddies at IH america. I took the wires off and had my buddy watch the # 8 piston and lined up the timing Mark with the piston then re installed the wires usinf a diagram. Cranked it kinda iffy, restabbed the dist then boom its alive dr frankenstein. I do think a valve is sticking though. Lastnight I tuned the carb and it ran like a dream. But this morning it has a put or it feels like its missing. The timing was spot on yesterday. The miss eased up once I turned it off and went in the store and came back out. Maybe some lucas oil stabilizer will help? It ran better after it ran for a but. Its the first day its been driven since I put it back together.

Thank you and I appreciate your help.

[Robert Kenney]

Nice!!!! Good job!!

Liberally,spray good carb cleaner in the carburetor (both barrels) while it is running at say 1500 rpm until it wants to quit and let it clear up. Repeat a couple of times... The sticky intake valve should clear up. Make sure you have new clean name brand fuel in the tank and drive the snot out of it. A long highway drive.
The name brands have better cleaners in them. The old fuel varnish on the valve stems can be a big reason for the sticking. The cleaner will remove it so oil can get in and keep it free...

[stephenjimenez]

Thanks! Yea I noticed that when I drive it for a while it goes away. I might also be the carb not being 100% correct. Ill work all the kinks out over the weekend.

[FDChappie]

I've found that marvel mystery oil is about the only thing that will cut the gunk that builds up on the stem of a stick valve. Use it in the gas and oil and see if it frees up.

Also sometimes a good italian tune up works too. These engines need a good hard run from time to time to burn out the carbon deposits. After all that is how they were designed to run in medium sized trucks.

[stephenjimenez]

So im not convinced its a valve. It only acts up when I start it for the first time of the day. Then when I start it again after that it goes away. There might be something in the carb bowl. Im ganna take it apart today to see if there is any build up of crap in there. Even in the morning it purs like a kitten when it idles its just when I give it more gas to accelerate or maintain speed. Does that sound more like a fuel delivery problem?

[Robert Kenney]

That's the symptom I've had and witnessed exactly. Limp at first cold start. You could hear it crank faster as the weak cylinder came up under compression that was not there...

After I worked new fuel in to it and a few starts with carb cleaner in the throat it has been fine since.

[Dealbreaker74]

Ok, sweet...you got it running again! Now help us understand the rest of what's going on.
Robert and some of the oregon fellas have experience with sticky valves. In a nutshell, fuel varnish "glues" the valve stem inside the valve guide. Not even the valve spring can return it to the closed position. But like rk says, it tends to get better with heat. The carb cleaner trick is good and with a long drive and fresh fuel should clear that up. No experience w/mystery oil personally.
But you are also mentioning a stumble or bog off idle or at low rpms. Is this a new problem? Have you looked at the accelerator pump? Should squirt a nice stream down the barrels when you rock the throttle.
Other than that, it looks like your carb May need some love. Any chance you could borrow another one to try?
Let us know what you find.

[Robert Kenney]

By the way I just went through another round of this with my Scout about 1 month ago... Started fine after a long spell of inactivity. Took it for a long freeway drive. Had lots of old fuel. Stopped at a buddy's house for a long evening and bbq. Went out and it would barely start. Had the bad limp upon cranking, like maybe 2 cylinders had compression. Had to run for about 2-3 minutes before magically smoothing out... The next morning the same thing... Smoothed out after about 2 mins. The following weekend I filled the carb bowl through the bowl vent and shot a bit down the carb. Started better. Filled the other tank with new gas and topped the other one off. Drove the snot out of it. Been ok since..