You still need a crank case vent, my friend.
Vent the crank to fresh air.
Run your pulse port between the carb and the compressor. You MIGHT have enough pulse to run the pump from there.
You still need a crank case vent, my friend.
Vent the crank to fresh air.
Run your pulse port between the carb and the compressor. You MIGHT have enough pulse to run the pump from there.
I never thought to pulse BEFORE the pump. DUDE THANK YOU!! I was ALWAYS thinking pulse after the pump and plug off the crankcase as to not loose pressure. I’m gonna go out here and unblock the gov port and use that as a vent. Then I will tap into the carb tube before the pump.
If I understand what you just said correctly, I don't think that will work.
Open the original crankcase vent to outside air so it will vent. Then tap your fuel pump pulse hose into the tube between the carb and the supercharger.
If I understand what you just said correctly, I don't think that will work.
Open the original crankcase vent to outside air so it will vent. Then tap your fuel pump pulse hose into the tube between the carb and the supercharger.
Yupp your correct I was all confused. So leave the gov hole plugged. Stock valve cover gets used as a crankcase vent like normal. Lastly pulse BEFORE the pump not after the pump. I was only going off what I’d seen others do. Pulse off the intake/valve cover so not seeing a setup pulsed before the pump just made me not think of it. I was counting the intake tube after the pump only as a place to pulse from. Not the part of the intake tube before the pump.
Now I think you see what I mean. There should be at least a little bit of pulse near the throttle blade. I am not sure how much pulse you'll have at wide open throttle, so be aware it might lean out at WOT.
Now I think you see what I mean. There should be at least a little bit of pulse near the throttle blade. I am not sure how much pulse you'll have at wide open throttle, so be aware it might lean out at WOT.
there isn’t much metering going on. I can keep an extremely short pulse line if I run it off the tube the carbs connected to. So as long as there is a bit of a pulse there i’m hoping it‘ll be more then plenty to do the job. Thank you again!
Thank you for doing this project! I am sure I am not the only one following along and learning right along with you.
Have fun and be safe!
Are you using an external pump pushing fuel into a carb with an internal pump?
Thank you for doing this project! I am sure I am not the only one following along and learning right along with you.
Have fun and be safe!
Are you using an external pump pushing fuel into a carb with an internal pump?
No external pump and yes I cut the gasket So now that I re-read the Hansen page about 5 times It finally clicked that doesn’t meter fuel that meters pulse.. it’s still running fine though? I just ordered a new diaphragm. This is a case of me getting ahead of myself. BUT none the less this project was beyond fun. My hacky setups of anything when I was younger never worked out to well. So this little engine working a little to well I‘ll take it. I’m absolutely going to build another one to match it.
I might be able to snag a tiller with a du bushing 5hp on Saturday. I want to use a smog pump on a 5hp this time with my long rod/piston combo and flywheel. And maybe a shop built tube from the pump to the inlet port. I also wondered about porting? the ports are almost to big now in stock form but moving 15-20 psi I’m thinking some significantly bigger ports would only help.
I think the boost moves the air through the ports much better than if it wasn't boosted. I don't know if you would notice a difference on the boosted engine if you ported it. Can't hurt, though.
I still have a parts 4 horse if you need it.
Magnificent! The stock briggs I/C starter rope pulley reads 94.5 and would you believe it ebay 60t supercharger cog style pulley reads 94.49! The ebay pulley is already a direct 24mm match to the raptor starter nut. I have ordered the driver pulley. now to measure and hunt down a driven. That smog pump output shaft better be 15mm it’s to predictable.
I’m trying to picture this thing with a cog belt/cog pulley system and a pre-bent correctly made intake pipe. Could look almost like a very old factory kit if I did it correctly.
Right now I run a 27” v-belt and a quick search to find a similar size belt leads to ONE eBay China listing that is a MM off. the pulley calls for a 16mm width belt and this is a 15mm width belt. It’s also like a MM longer or somthing but I have plenty of adjustment.
IF I can find a correct size driven pulley for the pump I’ll have my supercharger looking pulley setup.
This is why we re-search BEFORE we buy.. the outside diameter 686 belt wouldn’t work.
NOW the 740mm 13x686 labeled belt has an inner diameter of 27” 686mm like we measure v-belts. So I got the belt and diver pulley. Still working on what OD of the pump output is so I know the ID of the pulley I need.
I needed a caliper along time ago but sure enough I just checked 15mm and outside of 53mm so boom! I think I already remember seeing a direct or very close match on eBay.
The raptor starter nut is gonna push the whole belt system back meaning I don’t have to move the pump at all.
I ended with measurements of 100mm and 120mm and the closest I’m getting to that with cog pulleys is 100mm and 113mm.. I will have to adjust the pump on the gm tensioner arm and get a (slightly) different length belt. I’ll figure it out.
THAT WORKED! Take a caliper and measure out a 14.8 or so drill bit and fit both 15mm ID pulleys over it so they are centered. Clamp both pulleys together and drill your holes. Dime arrow straight cog pulley spinning on the pump. Now to get the pulley on the raptor starter nut and measure a belt.
One way starter clutch as to not kick off the raptor starter nut after it fires up. This drill was under a garage. The chuck is smooth as glass. This thing is massive.
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.