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Troubled Triad


Brettw

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I can use a bit of help, more for information purposes than actual repairs. I picked up a Sovereign today with the Triad. I had looked at this tractor a few months back and didn't decide to purchase it for what he wanted. Anyway, two months later and a reduced price and I picked it up. It supposedly ran just a few days ago, and it ran when I looked at it a few months back, although it wouldn't idle. Well today I go to pick it up and it will only run on one cylinder and is blowing back through the carb, so it must be a stuck valve. For all of the Triad gurus out there, what can I look for, other than a boat in need of an anchor?

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OK So I checked the Triads cylinders for function. Pistons are moving (as observed through the spark plug holes) valve train is all moving. Compression on one side not much at all on the other, and blowing back through the carb from one cylinder (I assume the one with no compression). So, I assume the intake valve on that cylinder has burned, or failed in some way that it is not seating.

There is one other possibility, but I do not know much about these engines at all. Is it possible that the cam on the bad side has jumped the timing belt? If it was out of time, that could cause no compression and blow back, no? Has anyone heard of or had experience with this possibility?

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I am sure someone has the answer. What you say about the cam makes sense with carb blowback but wouldn't the intake valve have to be stuck open as well?

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Intake valve was opening and closing as far as I could tell by observation, I pulled the valve cover to observe it. It is moving fully in it's cycle. But if it is burned or cracked, that would allow for the problems. If it jumped enough, the valves could be just fine, but opening on the upstroke and therefore the blowback. If this is an interference engine, then I would doubt that is the case, there would be major issues.

The timing belt can be accessed without tearing the engine down. And there seemed to be a lot of debris in the shroud, so that is why I am wondering if some crap got in between the belt and the cam gear, and it jumped? I have the engine out of the tractor, but have not gotten into taking much apart yet. If it is a possible jump in the timing, I will look into that. Otherwise the M20 is going in. I hate to do that, I wanted to just look at it for a while, all shiny and new sitting on the bench, and have it like that for as long as possible.:o)

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