78' 446 stalls under load - MyTractorForum.com - The Friendliest Tractor Forum and Best Place for Tractor Information
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post #1 of 2 Old 02-27-2019, 07:41 PM Thread Starter
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Join Date: Feb 2019
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78' 446 stalls under load

I just bought a 78 446 with the original 16 hp onan. It was running a little rough when I picked it up so I drained the fuel tank, installed new fuel line, filter, plugs, carb/ fuel pump kit. It idles great with no choke, but to maintain a higher RPM I have to choke it about half way. Then I have to slowly engage the snow blower or it will stall out. With the air cleaner cover off, when I engage the blower at idle and then raise the RPMs, the carb will dump fuel into the engine, then it stalls out. Any help would be greatly appreciated. Thanks.
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post #2 of 2 Old 02-28-2019, 09:30 AM
Hemlock Case Guy
Join Date: Mar 2013
Location: Michigan
Posts: 293
Re: 78' 446 stalls under load

It idles great with no choke, but to maintain a higher RPM I have to choke it about half way.

If we only focus on this, it is still a fuel mixture issue. The carb kit is not the only step to get a carb right again. It takes meticulous cleaning. Just spraying the surfaces of the carb will not get even close to what is needed. You also need to remove the carb from the engine with the manifold, then separate the two.

With the manifold off and the carb off seal off the surface between the carb and the manifold. I use duct tape folded onto itself. This is so that you can fill the manifold with water to check for leaks in the manifold. It will stand on the carb top. Zero leakage overnight is the goal.

Next, you need to see or learn each passage of the carb. A straw and can or two of carb cleaner is needed. With face protection, spray into each hole. Then if it comes out of a passage make sure it comes out cleanly. Sometimes I like to revisit each passage as I think that the first time loosens the build-up, the second frees it. You will use at least the whole can if you do it right. Every piece that can be removed has to be removed to be cleaned.
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