Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

Is there a simple way to disconnect the governor arm from the carborator? I've removed the bolts that hold the carb on but it won't slide off (It needs cleaned big time) because the of the linkage to the governor arm (wire rod and spring).  The shop manual says to remove one of the two screws that hold it on, but I'm not sure which one should be removed or what will happen to the governor if I do remove them.  I have heard that governors are really hard to adjust and I was trying to avoid that agrevation.  I've labels the two screws "A" and "B"  (one of them is really a bolt).

friiy wrote:

No, I have not started it  yet. Its on the docket for Sunday. I have to put the fuel tank back on. It was full of gummy stuff in the bottom that had to be cleaned out (done). I did find the original owner's manual and the correct spark plug cheap online. Those arrived.  The manual helped me set the gap on the plug and describes the correct choke and throttle settings for starting the YAMAHA.

Here it is running (see link).  It started right up.  What a difference with a clean carb.  I do think that the old fuel line is pumping rubber residue into the carb.  The oil was clear when it started but after about 30 minutes it was really gross.  The engine runs fine at idle. And it runs fine at a higher RPM.  The only issue I have (with the motor) is that when the snowblower is running with a heavy load the governor kicks in and raises the rpms way up. Far higher that I think the engine should be running.  Is this screw (on a part connecting the governor to the throttle) supposed to control high rpms called for by the governor?   This screw does not appear to be doing anyting. If not this screw is there a control elsewhere  for how high a governor is allowed to take the rpms? Note: you can see the screw in the photo below in the yellow box with a pink check mark

 

Here's the video:

http://vimeo.com/2411425

Screw A and B are you should not have to adjust....  unless someone has taken it apart... It looks as though no one has touched it..

The screw with the check mark is the high speed throttle plate limit,  if you tighten that down it will ( if I remember right) / should limit the no load top speed..

The unit,,as far as I  can tell from the video,  is running too fast at idle.  It should just put aglong about 500-700 rmp (I think).  and should run at about 3250 rpm at high speed.  ( I think)... Check the manual.  It should tell you...  Do you have a tach to see how fast it is going?

Just a note.... The checked screw and the screw on top of the  throttle shaft plate (low idle speed set screw) are screws that people try to adjust when the carb starts to clog up..

When the carbs start to clog up, they hunt and surge in rpm,  and will not sustain low speed rpm (idle)...  they adjust the screw so the carb is out of the idle range and continues to run...   But of coarse this is not right...

Good to hear it running,  does all the drive/ snow auger work ?

From the Desert,

Friiy

Your choke arm lever seems to bounce around alot, is it borken or just comming loose?

You may want to  peen the shaft back on the arm, and straighten it out. it will keep you from looseing the arm lever.

take a picture of the top of it, and I will tell you what I think should be done...

Friiy

friiy wrote:

I have no tach.  Sometimes auto parts stores will loan you things.  The manual says high rpm is 4000 and low rpm is 2000 (is "low" the same as "idle?").  There's also a horsepower rating but that is at a lower rpm like 3200 or so (under load?)  Wow 2000 rpm at idle. That might be about right. What do you think?

The engine RPMs   sound too fast to me too, its not you imagination.  That's why I'd like to adjust that limiting screw.  The screw does not look right the way it is. Its backed out so far that the little spring has no tension. But I don't know my way around those parts.  I do think that the rubber in the fuel line is breaking down and dissolving into the fuel.  I can see some black stuff in the carb when I look in past the choke plate. Not a lot, just a trace.  Where else would that be coming from?  The valve cover has a vent tube that feeds back into the air intake.  Maybe there's oil blowing by those valves. Hard to say.

You can imagine how great it was to hear it start.  The blower is a real beast.  I want to be able to snowblow the sidewalks in my neighborhood and so I will rarely have to turn it.  Until we get a snow I won't know if  was worth the effort.  It turns easier than some wheeled blowers that I have used but it is very heavy.  The blower part sounds like it needs a few new bearings (those are cheap) and I guess I'm going to have to open up the drive system to see why the shifting is sometimes "hit or miss."   In fourth gear it really moves along.  The belts need checked, I always worry that someone puts the wrong belt on.  It was used on a gravel drive so there are some paint issues.  I don't want to spend a lot of time on it until I know that I like how it blows snow.  

Are you sure the RMP (4000,2000) is that auger rpm?

Friiy

Can you send me the link on the manual? or post it..

Thanks,

Friiy

friiy wrote: Yes it shakes. You cannot balance a quarter on this one.  Apparently Yamaha engines are known for vibration issues  when carbon builds up someplace (the cylinder head?) .  The engine is mounted on big rubber bumpers and the fuel tank has its own set of rubber bumpers. I was thinking of wrapping some fine wire around the vibrating arm. I worried I'd wreck something if I started hammering away.  But if you have any ideas I'm game.  The shaking does not send vibration down to the choke plate (not yet anyway.)  If I find a tach, what do I point it at? The shaft coming out out to the pulleys and belts?

http://www.tinytach.com/tinytach/gasoline.php

This is the kind I have used for years, It has a induction pickup wire  you wrap around the spark plug wire ( around the insulation, you dont want to send engien spark down the pick-up wire)

Friiy

friiy wrote: This is from the manual to my snowblower's smaller 6hp twin.  The two engins are very similiar.