Need advice for another carb

[ghost civic]

I picked up this bike the other day.
A replacement carb is cheap, but a new tank (the old one is toast, super rusty) is $80!
Since the carb is attached to the tank, I can't just use any old tank. I have a plastic ATV tank that I want to use.

So, is there some other carb that will bolt up to this motor but use a normal fuel line? I was already working on bypassing the governor (which might not be working anyway) so any carb I get i will just rig up my own throttle linkage.

Any ideas?
Engine model is 135202

 

[Havasu Dave]

You can find a replacement tank cheaper than $80. For carbs, use Google search and specify this site. You will see a lot of examples of people using Tecumseh carburetors with part numbers 632230 and 632272. They are cheap on Ebay but are Chinese clones. You need to figure out a manifold for it. From what I gather, the OHV Briggs engines have an intake manifold that will work.

Another option is a Mikuni, or a Mikuni clone, both of which are 100 times better than the Tecumseh carburetor, but more tedious to tune, requiring a small selection of jets on hand. You still have to deal with the manifold.

You'll also have to deal with the throttle rigging, by pass the governor, and concern yourself with a fuel tank where the fuel outlet is higher that carburetor float level.

There are also pumps you can get for this purpose, made by Walbro, and Mikuni and some others. Virtually every carburetor between 19 and 22 mm at the throat will work on these engines.

Use google search. The search function on this site doesn't work as good as you need it to.

 

[ghost civic]

I got the bike to start and stay running long enough to try and ride it. It does ok upto 1/4-1/3 throttle. any higher than that and it bogs down and will die. I have taken the carb off and cleaned out all passages i could see. Might have missed soemthing or maybe just the crap in the tank is preventing the carb from getting enough fuel?
Or, could the pulse pump cause this issue?

Im trying hard to keep the repair cost to a minimum. I already have to try and clean or replace the clutch as it sometimes grabs when it shouldn't, IE at idle. Other times it works just fine. The brake pad has also separated from the band, so a new band brake will be needed. Im tempted to get a stock carb clone for $23 and see if the little screen on the pickup is able to keep out the crap in the tank.

If anyone knows what passage/needle could be clogged that is preventing me from going above 1/3 throttle LMK and I will try to clean it again.

Also, what is the base setting for the one large adjustment screw that is near the base of the carb?

 

[Havasu Dave]

1.5 turns. Yes crud from tank can block and clog screen. The way a pulsa jet works is that the "pump" uses intake vacuum to operate the diaphragm which draws fuel from the bottom of the tank to the upper portion of the tank where the shorter pick up resides. Fuel is then picked up in that smaller area and fed into the carburetor. ANY obstruction in either of the two systems can cause poor performance.

Beneath the screw in jet is a fixed jet than can be unscrewed with a flat blade screw driver, then cleaned. At that point, you can also use carb cleaner and an air gun to blow it out.

Highly recommend you get a rebuild kit, remove the tank and carburetor. Clean the fuel tank a good shop degreaser, and get all the crud out. Clean the carb with cleaner and air pressure, or soak in solvent and then clean with carb cleaner and air pressure. Reinstall bits from the kit, and it should work. Very simple.

Here is a web page with some good info. Scroll down.

Disassembly, Cleaning and Repair of Briggs Tank-mounted Pulsa-jet Adjustable Carburetor

Clutch grabbing might mean you are running too high of an RPM and it's engaging. Also, that bushing ONLY the bushing, should be oiled with 30wt every hour or so of ride time.

OldMiniBikes Warehouse link is above and they carry clutches and any band brake you might need.

 

[ghost civic]

Ok, that screw is 4-5 turns out. tomorrow I will set it to 1.5-2 turns out and see what difference that makes.

The clutch grabbing is all over the place. Meaning, one minute the bike is at idle and everything is good, and the next second the clutch is grabbing, making noise and since I either have the brake on or my feet down it kills the motor. The idle is for certain low enough that it shouldn't be grabbing. Other times the bike can idle for a bit without the clutch grabbing and it doesn't grab until I give the bike throttle...in other words operating just like it should. I will look up some teardown/cleaning videos and try that before buying a new one.

at least the frame, tires and engine are good. Just got to get the carb, tank, throttle linkage, brake and clutch all fixed up and it will be good to go.

 

[slow greg]

Ok, that screw is 4-5 turns out. tomorrow I will set it to 1.5-2 turns out and see what difference that makes.

The clutch grabbing is all over the place. Meaning, one minute the bike is at idle and everything is good, and the next second the clutch is grabbing, making noise and since I either have the brake on or my feet down it kills the motor. The idle is for certain low enough that it shouldn't be grabbing. Other times the bike can idle for a bit without the clutch grabbing and it doesn't grab until I give the bike throttle...in other words operating just like it should. I will look up some teardown/cleaning videos and try that before buying a new one.

at least the frame, tires and engine are good. Just got to get the carb, tank, throttle linkage, brake and clutch all fixed up and it will be good to go.

,,,,,,,,,,,,,,,,,,,,,,,,,,,look for an early briggs 5 hp carb and tank with the screw on cap.....bolts right up and the main jet is adjustable easier throttle linkage also.....try a new max torque clutch but with this much power maybe a better hillard

 

[ghost civic]

I ordered a rebuild kit for the pulse pump. Hopefully that will solve the issue. I got a throttle cable setup and installed a new brake band. I also took off the clutch and greased the shaft, that seems to have solved the issue of it sometimes grabbing at idle. She starts 2nd pull, idles good and will drive as long as you don't go above 1/3 throttle. Still manages to get upto 15-20mph on 1/3 throttle and I'm not light.

 

[Havasu Dave]

Still manages to get upto 15-20mph on 1/3 throttle and I'm not light.

That problem alone does not sound like your pulse pump. It sounds like you are running too rich at higher RPM. Can you run it while adjusting the needle? Might try slowly turning it in to see if it leans out and accelerates. Of course it could be opposite problem, because troubleshooting over the internet is nearly impossible. I'd say look at your plug, but flatheads tend to pass so much oil anyway, that you don't always get an accurate reading for fuel.

You should not use grease on the clutch. 30wt oil, as I stated above. There are some good videos Jim Donovan of Max Torque puts out that show servicing these clutches. But it is good to see you are making some progress.

Those Briggs pulsa carbs are also called kazoo's because they look like them. They work pretty good, but they were never designed to do anything but run at a constant, governed RPM. You may find it doesn't like to live with a decent idle AND a decent top end.

 

[ghost civic]

does grease end up attracting dirt? I would think that oil would just end up washing out pretty fast.

I've played around with the adjustment screw some, but it doesn't make much difference to when it bogs down. It seems to make more difference to the rpm's at idle.

When the new pump kit comes, I intend to do a more thorough job cleaning the carb than I did already as it kinda seems like something is still gummed up. But I will try running it again tomorrow and check the plug. Might not hurt to put a new plug in it either.

right now, it idles great. If i have to sacrifice the smooth idle for the ability to actually give it some gas then so be it.

 

[ghost civic]

I think the pump is the likely cause. Took it off just now and the gasket didn't look like that when I cleaned the carb the first time. It must have been worn and after being forced to move just fell apart. The bike had been sitting for over a year before I got it. I can't say that the new pump kit will for certain fix the issue, but I don't think this pump would be able to move enough fuel.

 

[Havasu Dave]

Yes, that pump was leaking. The reason we don't use grease on the clutch bushings, is that the grease heats up, melts, and goes away. Oil lasts longer. Those are "oil lite" bushings on those clutches. They are the only thing that should be lubricated. As I said, Max Torque has some videos out that explain that, and how to rebuild them. Good luck.

 

[Harquebus]

Oil that bushing, just a few drops of motor oil (like HD says), as much as every 2 hours of constant use. Most of them have what appears to be a bronze/brass/oilite bushing that by design is meant to be lower friction than just steel on steel...but it still needs oil.

Excessive idling or riding at an RPM low enough to cause constant clutch slippage will cause the oil to dissipate or burn off faster, which are two bad habits you don’t want to partake in.

What a pain huh? I rather like maintenance-intensive machines; brings back the intuitive man and machine relationship....

 

[ghost civic]

I got the new pump on and at first nothing. took the carb off again and found the main jet clogged. After that was cleaned I had my first WOT run. It isn't a power house down low like I thought it would be...might be the carb's settings or as another post mentioned this type of carb isn't meant for anything other than set throttle points.

But, it sure can get upto a good top speed. With the governor bypassed I didn't want to risk over-revving it but even so it can cruise at 30mph with hardly more than 1/2 throttle. It is kinda scary TBH.

I still have to take the tank off once more to give it a really good cleaning. Other than that, this project bike is good to go!

 

[Harquebus]

You’re not going to see blinding acceleration with a clutch and straight chain setup. It is what it is, but the top end can be exciting.
A torque converter or even a jack shaft setup can help though.

,,,,,,,,,,,,,look for an early briggs 5 hp carb and tank with the screw on cap.....bolts right up and the main jet is adjustable easier throttle linkage also.....

I agree. The older carbs with the slide choke on the rear has the adjustable jet. That’s the one you really want.
Wait a minute. Some of the adjustable jet carbs have the rotary choke too......

Disassembly, Cleaning and Repair of Briggs Tank-mounted Pulsa-jet Adjustable Carburetor

 

[joshua. c.]

have you gotten all the rust out of your tank yet?. I've had pretty good luck with filling tanks with rocks and water then shaking them a lot. they come out looking like they were sand blasted. I also try to get the tank dry quickly to prevent new rust. and I cleaned out the little bowl at the top very carefully with a sanding bit in a dremel tool. none of the engines I have done this to have had any rust related issues since.