620 snow blower is just weak. Please help.

Hello Everyone,
     I could really use some help. I recently acquired a 73 ac620. I thought I loved it. It seemed so capable that i Immediately took my last dime to hunt down a snowblower and have it delivered to Maine at great cost. I spent a couple of weeks troubleshooting small issues, finally got it all installed just in time for a huge storm. I fired it up and it was terrible. very poor power. I got a new belt  with plenty of tension. It only throws 4 inches of snow 5 or 6 feet when it does work. Any water in the snow at all and it plugs the chute almost instantly. Im pretty bummed out about it. I cant believe thats as good as it gets but im too unfamiliar with this system to troubleshoot.
Does the electric pto slip?
Is my pulley ratio off? sure seems stock to me.
my motor seems to run a little lean but its not that bad. Is it just weak at w.o.t.?
The thing is it seems to run fine til i hit the snow.
  Any ideas at all would be greatly appreciated
               thanks
        



Edited by joshuagurley - 24 Jan 2017 at 11:51am

Well, I just went out and tried again. 2 inches of icy snow.
Its not slipping. It throws ok for a moment and then the motor get bogged down.
I guess I'll clean the carb.
  Funny, it sounds like its running well but apparently its not producing power.
Any Idea where to get a carb rebuild kit?

I'm not big on fixes in a bottle, but I will have to 2nd the Chem-tool.  It has revived a couple carbs for me, in tractors that were sitting for a season or two.  There's a part of me that still feels like there shouldn't be a shortcut like this, but I try it first now, because it has saved me some time and expense.  Walmart has it cheap...$3?

I also run it in my SA200 welder with the Continental engine that has a MS carb on it and it really keeps it purring along and snaps open the carb when I start the arc without sputtering. 

Yes. 

Yeah, Lloyd is right on wit' dat one. If the timing is off on that machine, its not going to produce the power needed with the blower hanging on it. It should toss that snow quite far when running correctly. I would check the timing first, and then do what Jim mentioned to fatten up the fuel ratio. Cold dense air and a lean fuel mix will cause low power issues. A little twist on the enrichment screw will fatten up the mix. Should run better in the cold air. You may have to lean it a tic come the warmer months...

Welcome to the forum.  As you can see already, lots of knowledgeable folks to help out here.

Edited by macvette - 24 Jan 2017 at 11:37pm

Not to pour cold water on your fire Lloyd, but I hope the weather we're getting keeps right on moving into May!  LOL!  The older I git, the more I hate the cold weather and snow. So far, its been a very mild Winter for us here in Joisey...

Edited by Steve in NJ - 25 Jan 2017 at 7:43am

Maple in yard about to burst. I don't need the snow but grass ain't growin either

Have you checked you timing? also if you not turning 3600 RPM your not going to get it to work right. Mine would not get full throttle and would plug real easy, till I readjusted the linkage now it will blow like a champ . Don't get discouraged these are great machines and with a little love for say they'll out last anything out there .

And yes, timing and fuel mixture are both keys to a smooth running Onan. They run great but require some attention to keep them that way. I wish there was a way too get rid of the points, the box does move at times. Sure wish there was an electronic ignition to replace them. One of the down falls of the Onan. I have 2 720`s, but one runs better and is more reliable than the other. Of course one has 640 hrs vs 1014 hrs. So a fresh rebuild would be helpful. Reguardless, they do so much work and are some much fun to run. Amazing power out of such a small package. My grand children will enjoy mine after I'm gone, a little brother to my 190XT.

Mine has 1550+ hours on it.  Bought it approximately 6 years ago at about 1440 hrs, and previous owner said he thought engine had been worked on in 1998.  He didn't know how many hours it had on at that time.  Still runs pretty good, not perfect, but good enough for me.

Your blower will not move really wet snow very well. Below freezing, it should move it like crazy. Ive loaded dump trucks from behind with mine. Ive never run it at wot for blowing. I can tell you the belt needs to be fiddle string tight. And, they dont last real long. I keep a belt in stock. There should be no reason you are disappointed, when everything is working decent, they really move snow. Something is not right for you. Hope you figure it out, Trev.