Homelite 45cc & Walbro HDB-6B
 

I'm converting a Homie 45cc using parts from Wacker Engines. The carb adapter kit supplied has a Walbro HDB-6B carb, which seems awfully big to me! It has, I'm told, a 15+ mm venturi. Nice looking carb, but is it too much for this engine?[sm=confused.gif]

Thanks!

Kiv

RE: Homelite 45cc & Walbro HDB-6B
 

Not at all, this carb is phenomenal on this engine! I have converted nearly 100 Homelite engines with this carb. This is by far the best carb I have found for this engine. Scott Ellingson and I use it exclusevly on our large 45cc and larger conversion engines. Go ahead and use it and I guarantee you will toss the stock carb in the garbage. The difference is very noticible!

Peter would not sell you something that wouldn't work right. I hooked him up with these carbs and conversion parts for these engines. There are a lot of Homelite 45's out there running this carb.

RE: Homelite 45cc & Walbro HDB-6B
 

Hi, I have a Quadra 42cc and a Quadra 35cc that I have just got bavck into running order. I had read somewhere that putting a larger carb on these would give a boost in performance. I then found these carbs on ebay in a lot of 5 for a very good price, and went ahead and ordered them. Just waiting for them to arrive. It sounds like you (blackbaron) have good experience with these carbs. Doyou agree that I will get a little boost in performance. Also, any tips on setting them for initial runs.
Thx

RE: Homelite 45cc & Walbro HDB-6B
 

They should work just fine on the Quadra 35. You should see a gain of at least 300 rpm. The engine will also run better too. I have used them on my Homelite 33cc and 38cc engines as well with good success.

There are a few things you will need to do on these carbs.

You will need to take a cut-off wheel and cut down the long adjustment needles to about 1/2" and then re-slot them for a standard flat blade screwdriver. If you don't cut them down, they will rattle out.

The pulse hole line on the carb face is not positioned at 12:00 like it is on the Walbro WT or WA carbs. It is like positioned at 3:00 so it will not line up on your manifold. This is where you will need to tap your crankcase and tap the carb for a remote pulse as pictured below.

Initial Needle settings I turn them out to 2-1/2 turns for both Low and High. Go to my website under the troubleshooting tab and on this page I discuss a few things about this carb.

RE: Homelite 45cc & Walbro HDB-6B
 

Thanks very much Blackbaron for the excellent info. In your response you said "This is where you will need to tap your crankcase and tap the carb for a remote pulse as pictured below." I went to your website and looked at your 'Tips' section. (Excellent info by the way.) Is that what you were refering to in your above quote as 'picture below'?

Thanks again!!!

RE: Homelite 45cc & Walbro HDB-6B
 

Yup, thats the page. I add little tid-bits here and there. I will be adding a section on how to modify the Zama C-1 carb for pulse tap on the face of the carb. This current setup on this carb is for remote pulse only.

RE: Homelite 45cc & Walbro HDB-6B
 

How big is a throat on these carburetors? Is it 14 mm?

RE: Homelite 45cc & Walbro HDB-6B
 

Could not find the HDB-6B listed Just the HDB-6:
http://wem.walbro.com/walbro/product...um=HDB%2D6%2D1

showing 15.88 mm venturi.

How does the outlet diameter of the carb compare to the factory carb heat insulator I.D? Also to the intake on the head?

RE: Homelite 45cc & Walbro HDB-6B
 

Hello BlackBaron,

I finally received my new carbs. It looks like I will have to do quite a bit of modificationto the carb mounting block to get them to fit on the Quadra's., ie: cut of carb positioning tabs on the CBM, trim one edge of the CBM off to accomodate a lip on the edge of the carb, enlarge the carb side of the intake port on the CBM to match the new much larger carb throat. Is this actually going to be worth all this? Or, is there an alternative mounting block I could use on this engine? (Perhaps you sell something through BCMA that would work...)
Any insights would be appreciated.

RE: Homelite 45cc & Walbro HDB-6B
 

Just to clarify... what I have called the carb mounting block, is also called the carb insulator, or carb adapter.

RE: Homelite 45cc & Walbro HDB-6B
 

Mike,
The throttle bore is 3/4th inch (19mm ) and the venturi is 16mm, but it has 40 cast into it, which is 15.88mm. I think that they are allowing for two flat areas in the venturi which reduce the effective area.

Dave

RE: Homelite 45cc & Walbro HDB-6B
 

HI,
If you wanted to keep it simple, you could just install a good Walbro WT carb with a 13.49mm venturi. It would be a direct swap and power would go up considerablely, without all of the modifications. Most of the 42cc to 50cc engines use this carb size.

Dave

RE: Homelite 45cc & Walbro HDB-6B
 

Well, I got the carb adapter and carb mounted, muffler installed, flywheel trimmed, prop hub made & fitted, and beam mounted (Hangar 9 mounts) to a test stand. The only prop I had to try it with was a 18x8 Dynathrust . Guess I'll definitely need a bigger prop ( 20x8 or 22x8, probably) 'cuz I was able to spin up to 8500+ with no effort at all!

I've got everything balanced as well as possible, but now I am concerned about vibration. Although the firewall in the plane I'm building is 1/2" laminated ply I'm wondering if I need to set it up with some kind of vibration isolation system. Seems like the longevity of the plane would be improved, would it not?

Opinions/suggestions, please!

Kiv

BTW, I plan on putting this in a scratch-built Santich Ultra Hots (sorta 1/4 scale). Supposed to be around 14 - 15 lbs or so. Too much engine? Not enough? Just right?

RE: Homelite 45cc & Walbro HDB-6B
 

It'LL go real good

RE: Homelite 45cc & Walbro HDB-6B
 

Is the HDB carb too big for a 32cc engine it's going to be supercharged to make up for the extra fuel but will the HDB carb work [sm=71_71.gif]

RE: Homelite 45cc & Walbro HDB-6B
 

blackbaron - What is your website?? PM me if you can't openly post it in the forum please.

Thanks,
AV8TOR

RE: Homelite 45cc & Walbro HDB-6B
 

My homie 45 has the stock carb with stock insulator. What would I need to upgrade to the HDB-6b. From all I've read, this sounds like the way to go with this engine?

RE: Homelite 45cc & Walbro HDB-6B
 

I got a HDB carb for my mcculloch 32cc engine the engine roars it to scary to rev it to the max the rpms went way up but of course I didn't put on a load on it. I think i'm going to drop my supercharger project this carb did it for me[sm=teeth_smile.gif][sm=thumbs_up.gif][sm=thumbs_up.gif][sm=thumbs_up.gif].