Papee
04-25-2014, 04:56 PM
First a little background on the carbs. They are Tillotson carbs made for the Army mule. The carbs were used on a twin cyl engine much like the 084. These twin cyls are a 42 cubic inch motor which is exactly half of the 084. The good thing about these crabs is that they are made to be on a motor with varying rpms which the carbs on a 084 are not, they are designed to run at a constant 3600 rpms.
These carbs also have air and fuel adjustments as well as a accelerator pump making it a good choice for these motors if run as a dual setup.
The carbs.
http://miniairboatassoc.com/084/dualcarbs.jpg
The animal they are designed for, the Mule.
http://miniairboatassoc.com/084/mule.jpg
I had some time to spend in the shop today but I didn't get much accomplished other than some head scratching. I am making or trying to make new intakes to allow these carbs to be used on our 084s. I didn't want to just build a box plenum because they are just not efficient and do not flow well. If you have any corners the gas will get trapped there and not flow well. I am trying to design intakes that will get the best performance from these carbs using round tube.
The problem I am having is becasue of the magneto position it is hard to get the right placement on the carbs. After looking at if for some time I see that I have two choices. One would be to raise the intake tubes so the carb on the mag side has room above the mag, this would require that I also raise the other side to match to make both intake sides the same. The other is to scrape the "use the stock intake tubes" idea and make a new set of intakes that would bring the carbs to the outside of the engine right above where the intake tubes come out of the cylinders.
Like this
http://miniairboatassoc.com/084/dualintake.jpg
The problem with this is that it would be a nightmare to figure out a reliable throttle linkage. I'm now trying to figure out a way to stack them. There are other ways to do it also by making a plenum in the end of the stock intake to accept the two carbs but this just would not be efficient.
Any ideas would be appreciated. ;rasta;
These carbs also have air and fuel adjustments as well as a accelerator pump making it a good choice for these motors if run as a dual setup.
The carbs.
http://miniairboatassoc.com/084/dualcarbs.jpg
The animal they are designed for, the Mule.
http://miniairboatassoc.com/084/mule.jpg
I had some time to spend in the shop today but I didn't get much accomplished other than some head scratching. I am making or trying to make new intakes to allow these carbs to be used on our 084s. I didn't want to just build a box plenum because they are just not efficient and do not flow well. If you have any corners the gas will get trapped there and not flow well. I am trying to design intakes that will get the best performance from these carbs using round tube.
The problem I am having is becasue of the magneto position it is hard to get the right placement on the carbs. After looking at if for some time I see that I have two choices. One would be to raise the intake tubes so the carb on the mag side has room above the mag, this would require that I also raise the other side to match to make both intake sides the same. The other is to scrape the "use the stock intake tubes" idea and make a new set of intakes that would bring the carbs to the outside of the engine right above where the intake tubes come out of the cylinders.
Like this
http://miniairboatassoc.com/084/dualintake.jpg
The problem with this is that it would be a nightmare to figure out a reliable throttle linkage. I'm now trying to figure out a way to stack them. There are other ways to do it also by making a plenum in the end of the stock intake to accept the two carbs but this just would not be efficient.
Any ideas would be appreciated. ;rasta;