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:

Is the adjustment needle that  you are refering to identified as #6 in the diagram above?  Sure, I can try to spray carb cleaner in there. I do not know where the venturi is or where its small holes might be. 

I did clean out the gas tank and flushed out the gas lines.  I could not locate replacement diaphrams for the (Mikuni?) fuel pump so I chickened out on the idea of opening it up. I just soaked it an flushed it out a few times. It does seem to be working.  I would agree with your recommendation for a fuel filter. I think this is the weak link in the fuel delivery system.  There's a small sediment bowl under the gas tank and a filter screen on top of the tank for large particulates. But there is nothing to filter the finer particles.  That said, I would not want a fuel filter that would interrupt the function and flow of the fuel pump.  

Sorry,  The venturi is the narrowest part of the carb throat...   The holes I am talking about are where the throttle butterfly wipes past the inside wall of the carb as the butterfly opens from fully closed postion.. on the same side of course as the needle adjustment screw.

Have you tried to start that thing up yet?  Or check for leaks?....   It  should start/run,  you just need to find out if you need to replace the inlet needle at this point.

Friiy

I have been dying to go get the carb back on and try it out. But family stuff got in the way all weekend.  The needle valve looks good to me but I would like to polish the small channel that it slides up in to. I noticed before that it would sometimes stick or hesitate when it moved up or down.  The snowblower has not run in a long time and I thought I would put some fresh oil in the crank case. Here's an image of the needle's  tip . 

 

You can polish the channel it rides in,  but do not polish the area that the rubber tip seats at...  

Friiy

friiy wrote:
The carb is completely back together..  Maybe I should have assembled the main jet using anti- seize.  It was so tough to get out. But I didn't .  I'll be amazed if the the large O-ring gasket around the top of the bowl doesn't   leak.  A new one is close to $20, so I take my chances for now.  

The large bowl rubber  ring is not nuch of a seal,   fuel only reaches that point when the engine is tipped. or if the inlet needle is leaking past overfilling the carb...

Friiy...

besides.... that ring is most likly cheeper from a aftermarket company like Rotory, Arnold , Billues.... or so on.....

Plus,   that ring may be the same as a Honda bowl or a Kawasaki...

Friiy

Did you start the Yamaha yet?

Friiy

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