H70 Techy running, but still need help

[Shuboxlover 474]

I rebuilt the carb, it went really smooth. I was worried about some of the stuff I heard, but I was actually surprised it went as good as it did.

I put it back together, pulled about 5 times, and it fired up. I would say it runs good....not great, on a scale of 1-10, 10 being it runs perfect, I'd give it a 7.5.

Can you guys tell me what the initial setting for the carb is, then I can fine tune it from there?

Thanks

[Anglo Traction 759]

Assuming it is a Series 1 type Carb, the Pre Sets are - Main 1 1/2 turns and Idle 1 turn.

Happy New Year.

[Shuboxlover 474]

Assuming it is a Series 1 type Carb, the Pre Sets are - Main 1 1/2 turns and Idle 1 turn.

Happy New Year.

Is the main the one that's on the bottom of the bowl? :ychain:

[buckeye 2]

Yes, the main is the one on the bottom

[Shuboxlover 474]

Thanks Bryan, I'll try and get it fine tuned on Sunday...

Thanks :ychain:

[Shuboxlover 474]

Well.. started with the initial settings and adjusted from there.

I still can't get the thing to idle at a low RPM...It runs just fine as long as the throttle is about 1/2 or more. If I adjust the idle screw down (not the idle adjusting needle) the screw that actually sets your idle rpm, the thing surges and then dies, I just can't get it to idle good. Like I said, it runs really good in the upper rpm range, I can drive it around great with no hesitations or misses.

What do you think is the problem? :ychain:

[Anglo Traction 759]

What do you think is the problem?

Hi, I'm not a worldly expert on these, but I used a Manual when I worked on one for the first and only time (so far).

The most likely problem is that your getting air in through the Throttle Shaft if it is worn and sloppy in it's bore. It needs to be a snug fit.

Or there is a leak in the gasket joint (Carb to engine)?

Or the Idle Air Bleed passage is blocked?

When you fitted the Idle Needle (just above the Bowl), was the Carb held upright?.

I ask this because there is a Metering Rod that can be trapped by the Idle Needle if the Needle is screwed in with the Carb upside down. This would give a False Closed setting before unscrewing one turn for Pre Set.

You don't say if your applying Choke while doing this? Is the Choke shaft worn?

I have read on this Forum that they are tricky to set up. Maybe I was lucky.

So persevere and if if this doesn't work, hopefully someone with more experience will Chime in.

Rgeards.

[mr.pipes 4]

What do you think is the problem?

The most likely problem is that your getting air in through the Throttle Shaft if it is worn and sloppy in it's bore. It needs to be a snug fit.

Or there is a leak in the gasket joint (Carb to engine)?

Some sort of air leak would be my first guess. Did you replace the gaskets? Throttle and choke shaft play is common on these. You can spray some carb cleaner around the shaft when it is running. If this changes the rpm then you know air is getting through these areas. If so, you can try to seal it up with one of those felt pads that go on the bottom of chair legs to prevent scratches on hardwood floors. If all else fails, you can get a Oregon replacement carb for $50 shipped.

[Shuboxlover 474]

I did not replace any of the gaskets...

They all looked reusable.........except one i guess

Maybe I should start there and see if that helps. If I remember right, the one that is suspect is the one that goes between the carb and the carb block (the piece between the carb and engine).

[Anglo Traction 759]

I did not replace any of the gaskets...

They all looked reusable.........except one i guess

Maybe I should start there and see if that helps. If I remember right, the one that is suspect is the one that goes between the carb and the carb block (the piece between the carb and engine).

Yes, I know that Spacer Block well, a ***** of a design with concealed Posi Head Screws.

I 'Modded' that Block to carry Sunken Hex Head Bolts bonded in (captive), so I could just run a Lock Washer and Nut on from the outside and got them tight with some Gasket Sealer smeared on the mating faces .

Are your Throttle n Choke Shafts ok?.

[Shuboxlover 474]

Oh ya, I forgot to mention that in my previous post.

I purposely checked both shafts for play and they were surprisingly tight, so I don't think that is the issue. The holes were the linkages connect are not all slopped out either, I don't think this thing has alot of hours on it. :ychain:

[buckeye 2]

I would try playing with the needle adjustments. Mine had to be set a little rich to idle good. those carbs are touchy to the slightest adjustment.

[Shuboxlover 474]

I tried that....I went all the way back in (1 1/2) turns all the way out to about 3 turns out and it still didn't seem to help the situation. :ychain:

[buckeye 2]

When you rebuilt the carb, did you set the float height? when the needle is closed, the float has to be a certain distance away from the carb, but cant remember what it is off the top of my head. As far as the main and the idle needles, try starting out a1 1/2 on both, and dont tune until the engine is at operating temp.

[Shuboxlover 474]

Yes, I did check the float height, I think I was supposed to use a #4 drill bit and lay it across the carb under the float to check....at any rate, it was set correctly.

[Anglo Traction 759]

I think with what we have established up to now is, as Bryan says " an adjustment problem.

Best to start again on the Needle Pre Sets. Idle speed Screw (Top) set to the point where it just touches the Throttle/Plate and just cracked open. Air Filter fitted.

Start it up and get running to temp at 1/2 speed for about 5 mins.

Increase to near full Throttle and Adjust Main Needle to obtain smoothest running position. You should not need to adjust this further now.

Throttle back slowly until you reach idle speed. If it dies before you get to Idle, then you need to adjust the Idle Needle Screw depending on whether it's flooding Rich (close it) or starving Lean (open it). Do this 1/8 of a turn at a time until it starts/runs on idle easily.

Set Throttle to fast idle and adjust again CWise/CCwise in 1/8 steps until it runs smoothly on low idle.

Lastly , you can increase the Idle just a Tad with the Top Adjusting Screw

You should also test it while under load.

Float setting cleaerance that Bryan mentioned should be 11/64" .

Keep at it!, you'll get there. Please obtain a Manual for it, they are priceless .

[Coadster32 793]

I've always just set the float by flipping the carb upside-down and getting it parrallel with the bottom casting. I've never had a problem with that. I'd also suggest a fuel filter, and inline shutoff. Easy not to do this once you get it going, but will bite you later down the road. Sounds like you're on the right track and with good guidence. You will get it. :ychain:

[Anglo Traction 759]

I'd also suggest a fuel filter, and inline shutoff. Easy not to do this once you get it going, but will bite you later down the road.

Check ! this is a must . good advice if you haven't already done this.