- Joined
- Jul 16, 2007
- Messages
- 3,028
- Reaction score
- 1,119
Hi everyone,
Just a quick update on the running of the engine. I have almost 20 minutes of running time on the engine. Not all at one time but in 4 or 5 starts. I'm discovering things that needed to be redone. First of all I made a new needle for the carb. I made it out of a large sewing needle so it has a much finer adjustment. Next up was the motor mount bolts, the 3-48's kept coming loose so I went to 5-40's with stainless washers. When I made the base the uprights were fitted into the runners and held in place with one 2-56 screw per side. These also came loose so I put two 3-48 screw per side.
While running the engine the other day at my buddies place it would start and run great for about 3 minutes then you could see the fuel being pushed back away from the carb. My buddy said it looks like it's vapor locking, I said it didn't seem like something this small would do that. While I was fiddling with the carb a rested my hand on the intake manifold and WOW, it was as hot as the head. What was happening was the carb was getting so hot that when the gas fed up to it it was boiling the gas and pushing it back away from the carb. We blew on the carb and manifold with an air gun till it cooled down, hit the starter and it fired right back up.
Last night I took the intake manifold off and machined .04 from the .125 flanges and made insulator pads. Today I ran the engine until I thought the cylinders were hot enough, about 4 minutes, and felt the manifold, it was barely warm. I shut the engine off and restarted it several times. I fired up and ran great. Another gremlin taken care of.
My buddy had a piece of steel plate .75 thick. He surface ground it for me and I'm going to make a base for the engine. It will be mounted on rubber bushings to try and isolate some of the shake. At home I can clamp it to my workbench but at a show I might not have that option so this should allow me to run it without it dancing off the table, as long as I don't rev it to high.
We put a tach on it for this morning's run and it will idle down to about 900 rpm. On the high end I've had it up to about 5000 rpm but at that speed it starts acting like the Tasmanian Devil.
All in all I'm thoroughly pleased with the outcome.
George
Just a quick update on the running of the engine. I have almost 20 minutes of running time on the engine. Not all at one time but in 4 or 5 starts. I'm discovering things that needed to be redone. First of all I made a new needle for the carb. I made it out of a large sewing needle so it has a much finer adjustment. Next up was the motor mount bolts, the 3-48's kept coming loose so I went to 5-40's with stainless washers. When I made the base the uprights were fitted into the runners and held in place with one 2-56 screw per side. These also came loose so I put two 3-48 screw per side.
While running the engine the other day at my buddies place it would start and run great for about 3 minutes then you could see the fuel being pushed back away from the carb. My buddy said it looks like it's vapor locking, I said it didn't seem like something this small would do that. While I was fiddling with the carb a rested my hand on the intake manifold and WOW, it was as hot as the head. What was happening was the carb was getting so hot that when the gas fed up to it it was boiling the gas and pushing it back away from the carb. We blew on the carb and manifold with an air gun till it cooled down, hit the starter and it fired right back up.
Last night I took the intake manifold off and machined .04 from the .125 flanges and made insulator pads. Today I ran the engine until I thought the cylinders were hot enough, about 4 minutes, and felt the manifold, it was barely warm. I shut the engine off and restarted it several times. I fired up and ran great. Another gremlin taken care of.
My buddy had a piece of steel plate .75 thick. He surface ground it for me and I'm going to make a base for the engine. It will be mounted on rubber bushings to try and isolate some of the shake. At home I can clamp it to my workbench but at a show I might not have that option so this should allow me to run it without it dancing off the table, as long as I don't rev it to high.
We put a tach on it for this morning's run and it will idle down to about 900 rpm. On the high end I've had it up to about 5000 rpm but at that speed it starts acting like the Tasmanian Devil.
All in all I'm thoroughly pleased with the outcome.
George