jetG23

Hello , I have a 45cc homelite that I have converted and want to upgrade the carb . but this model has the pulse hole at 6oclock. and the carb I want to use is around 4oclock

I am wondering if I can tap the carb and crank case to make it external pulse ?? If so, can someone give me some pointers on how ?? I have both the solid mount 45cc and the one with the rubber boot.
from what I read the one with the rubber boot has mare aggressive timing. anyone have a preference ??

Thanks
JET

rcairboater

aviator will chime in on this one. awesome guy to deal with, I have purchased several engines from him.

rcairboater

here you go,
http://www.rcuniverse.com/forum/engi...mie-forum.html

jetG23

Cool man ! Thanks !!

av8tor1977

My Feedback: (6)

Did that answer your question? I use 8-32 pressure taps. There is a spot on the fuel pump cover of the carb, a boss, that is perfect for drilling and tapping for the pressure tap. Then anywhere convenient on the block/crankcase gets a tap as well. Keep the line short as possible and use stiff tubing to connect them. (Regular Tygon or rubber tubing will work.) It is not necessary if the gasket blocks off the original pulse hole, but when I convert them to external pulse I usually block off the original pulse hole with a little JB Weld.

Here's a pic.

AV8TOR

jetG23

Yes, that will give me what I need for the carb . Im not exactly sure where to tap into the case... it is case and jug all in one. Can I tap in any where below the piston ?

av8tor1977

My Feedback: (6)

Yes, anywhere below the piston. I try to keep mine away from where the crank might sling fuel into the line if you had the engine flooded. It is best to choose an area that is somewhat thick, and be careful not to get chips into the engine/bearings.

AV8TOR

rcairboater

Can you post up some pics of the engine and boat?

jetG23

Thanks Avi8tor ! I'm going to disassemble the engine anyway so no worries about the chips. I have a set of Frank Bowmen rings to install ;-) @ rcairboater, I will try to get some pics tomorrow ! Its my black widow boat. she is in transformation right now...lol

jetG23

Where can you get pressure taps ? auto part store ? Also the carb I have is a Zama EL32 with a 15mm venture... I think it should really wake this engine up ! I hope...lol

av8tor1977

My Feedback: (6)

No, they are a hobby store item, like here: http://www3.towerhobbies.com/cgi-bin...&I=LXD623&P=ML

AV8TOR

jetG23

jetG23

I can get some better close ups if you want !

rcairboater

If you have the time, that would be good. What size round bar did you use on the rigging? Is this the engine you are speaking of?

Larry882

Here is a picture of a 42CC Wildthing motor showing where I drilled the case for a pressure fitting. I used a 8-32 screw and drilled threw it with a 3/32" drill bit. You still need to use some type of fiber block to keep the heat from traveling to the carb.

av8tor1977

My Feedback: (6)

That air boat looks cool and I bet it hauls BUTT. You can't even say A $ $. here....

Yeah, heat isolation is essential for the carb. I did a Stihl 62cc engine, and I used a carb insulator, but the mounting screws went through the carb and into metal. Enough heat was transmitted through the screws to the carb for it to get too hot and it was a problem. I had to make a new insulator that mounts the conventional way; the insulator bolts to the engine itself, and the carb bolts only to the insulator. Then I had no more problems.

AV8TOR

jetG23

http://youtu.be/8Zsp2DGJggU

http://youtu.be/KwUxn38puio

Here are a few vids of the boat! @ larry That is just what I needed to for me to do my case !! Thanks guys ! RCairboter, The engine on the boat is the one I want to tap for external pulse .... Thanks for the input guys ! I will put it to good use ;-)

jetG23

rcairboater

Thanks for the pics. What exact engine mods did you do with the conversion? Intake, exhaust, compression?

jetG23

Its stock other than the muffler and prop hub . Thats why I want to put a bigger carb on it and maybe open the exhaust port a little more.

jetG23

Its stock other than the muffler and prop hub . Thats why I want to put a bigger carb on it and maybe open the exhaust port a little more.

Scota4570

"this model has the pulse hole at 6oclock. and the carb I want to use is around 4oclock" The easiest way is to make a track or groove connecting 4-o'clock with 6-o'clock in th intake manifold. Go slow and use a tiny dremil cutter.

av8tor1977

My Feedback: (6)

Ha, that's funny Scota4570! I just clicked on this thread to mention that very thing as I had forgotten to mention it earlier. (I always just go with external myself.) And then here I see you had made the very same post I was thinking of making. Good call.

How are your projects doing? You have that Stihl 65cc Four Mix from me right?

Take care,
AV8TOR

jetG23

Thanks for the tip Scota I did experiment with it a little.... I will probly go external, since the intake manifold will have to be modified for the larger carb. it will most likely be opened up to the point that it might be in the pulse channel on the intake manifold. I do have some delrin to make some intakes for the 45cc I have, that has the rubber boot style intake. we will see how it goes ! I ordered my 8/32 pressure taps, so they should be here this weekend

Avi8tor, do you think that I should install my frank bowman ring after I finish with the carb mods ? or before ?

av8tor1977

My Feedback: (6)

I would install the Bowman ring, run it a bit with the present carb to let the ring break in a bit, and then do your carb experimenting. When possible, when I am modifying things I like to make only one change at a time. That allows you to quantify each improvement, and if you run into any problems, isolate them, even though many improvements one does to an engine usually compliment each other.

Same for me on the pulse hole. I often have to open up the intake so far that it either gets into the pulse hole in the manifold adapter, or damn close. I usually fill the original pulse hole with JB Weld before I start opening up the adapter. A sanding drum in a Dremel tool works best for opening them up. Don't try using a drill bit; the material is too soft and the large drill bit will "catch" in the material and make a big mess of everything.

AV8TOR