By larry conklin on Unrecorded Date: Edit

My Amphicat has a Tilotson carburator that constantly is in need of adjustment. It won't start on the same settings that it needs to run and it won't run on the same settings it needs to start. Any help would be very much appreciated. Also does anyone have a drawing or a diagram of this carb? (fuel supply on the bottom seems strange) Thank you one and all!!!!!!!!!!!!!

By Kevin Percy on Unrecorded Date: Edit

Larry,
Check this link out

http://www.mercurysnowmobiles.com/hrcarb.htm

Good Luck,
Kevin

By r.wolf on Unrecorded Date: Edit

larry, welcome to the club. david berger said it best as you have to run the machine several times a month. the tilly's are great alky and gas carbs, but runnin premix the oil sluggs 'em up. extra cleanin' is the norm.
tell us about it, when ajusting and tryin to get the bastards to start.
neat link kevin.

By Kevin Percy on Unrecorded Date: Edit

Those carbs, as I'm sure most of you guys know, were used on most snowmobiles from the 60's, and those used premix. Now they are tempermental, I won't disagree there. I would suggest that keeping the fuel system clean helps a lot. Keep your fuel fresh, try not to let any water in the tank (use a good gas cap, and don't fill the tank in a rainstorm) and don't use any kind of gas-line anti freeze, it dissolves the rubber in the diaphragms . If the machine is going to sit more than a week I would suggest pinching the fuel line and letting the engine run out of fuel to shut it off, that helps prevent the fuel inlet needle from sticking in the closed position.
The link was the first one I found with a diagram, I don't know anything about that guys that own the site.
Just my $0.02, I'm not an expert by any means.
Kevin

By liflod (Liflod) on Unrecorded Date: Edit

Cut the Tillotson mounting studs off flush with the intake manifold. Drill the holes to mount Mikuni mounting studs and put a Mikuni on it.

By Bubba Hunt on Unrecorded Date: Edit

Larry, I haven't been following your problem as I have been buzy lately, but I did see a post recently about someone wanting to use an electric fuel pump on a machine. I remember that another wrote not to use one as it would flood the carb.
Well, just for giggles I do have an opinion as most do. I was haveing problems with my 32 hp generac on my Hydro. It just didn't seem to go well under a full throttle load.After cleaning the carb,fuel tank, replacing filters, etc., I finally got smart enough to ask an old timer who worked on small engines.
He said,a friend of his had just converted a trackster to a Briggs Vanguard and it just didn't seem to run right. After some testing they put an electric "LOW PRESSURE" fuel pump from Nappa. It was a 1.5 to 3 lb. pressure pump. The problem was that because the tank was behind the seat and about 5-6 feet of line and there was about a 3-feet lift to the engine that the little vacuum pumps just couldn't cut it under full throttle.I can tell you that I put that low pressure electric pump on my generac and it took off like a scared house cat.
Those little vacuum pumps work fine on snow machines because the fuel tanks are close, but the bigger engines have a need for a bit more power when they are pulling from a tank in back.
Oh, I,ve heard the stories about how the electric pumps will flood the carbs, but for my engine it was the answer.I'm not talking about the 7 lb. pressure pumps that are used for cars, I'm talking about the LOW pressure pumps. Well heck, there is my opinion, take it or leave it.I have an idea it may solve a bunch of those "carberator" problems that we all have.
Bubba

By liflod (Liflod) on Unrecorded Date: Edit

I don't think the Tillotson's have enough suction at cranking speeds to get enough fuel to the carb and get it to start. Bubba has a good point about the electric fuel pump. You may want to try a another small tank above the carb to see if gravity feeding it will help. The other solution is a primer system to squirt fuel into the intake to get it to start. Make sure your fuel line is run higher than the carbuerator so when the pump is not pumping, there is a little bit of fuel being gravity fed to the carb. I would also suggest a fuel filter in the line above the carb to add a little more capacity to your gravity feed system. Once the engine does come to life, the pump will start working.

By david berger (Davidrrrd) on Unrecorded Date: Edit

YUP AS LIFLOD HAS SUGESTED A PRIMER PUMP DOSE WONDERS, I HAVE ONE ON MY TERA-JET AND IT WORKS GREAT, BEST PART IS IT FEEDS FROM A T FITTING RIGHT BY THE TANK! SO PRIMER PUMP CAN GET FULE ANY TIME YOU NEED IT TO PUMP, EASY STARTS WITH THE PRIMER PUMP, A GREAT MOD. DO IT