4 Stroke HS Carb...

[phoobarnvaz]

A carb is a carb and the function is to feed gas so don't really make a difference if the engine is 2 or 4 stroke. You can even run a chain saw carb on a 4 stroke if you drill for a puls line for the pump,then the tank can be mounted anywere.

That's why these guys before the 90's and such were able to switch out the manifold on whatever engine they were using and use a custom carb for better performance or more power. I take it that I was doing exactly the same thing...only on a much smaller scale. Still fascinating that it seems like people are just starting to do this within the past year on the 4-strokes with the new manifolds.

I know another choice I had was a diaphragm carb for the 4-stroke. Seen them on sale at Dax and other places...but for myself...wanted something where I knew I could get the parts...especially since it seemed like Kings and Dax was the only place you could get a 4-stroke carb. The new manifold and the NT carb fit the bill.

What is sad is they done away with ajustable jets and went to fixed jets so now you have to chane or drill them,were you just had to ajust them before...........Curt

I helped rebuild carbs in the 70's and 80's on some cars I owned...but I don't remember ever coming across any that were adjustable. I seem to remember that you went to the same store you got your "kit" and told them what size of jet you wanted to put in the carb. Had to do this when I put a Holey carb from a 4-cylinder Ford on my VW Type 3 when we took off the dual carbs because they were too difficult to tune without special equipment.

I hate this...makes me feel old. ;(

 

[curtisfox]

This is the kind i was talking about,and you can still by them new, And kits can be had at any small engine place. You can see the ajusting jet on the bottom and as well as the ideal jet on the side http://www.amazon.com/REPLACES-CARB...qid=1414585139&sr=8-8&keywords=tecumseh+carbe. .......Curt

 

[phoobarnvaz]

This is the kind i was talking about,and you can still by them new, And kits can be had at any small engine place. You can see the ajusting jet on the bottom and as well as the ideal jet on the side http://www.amazon.com/REPLACES-CARB...qid=1414585139&sr=8-8&keywords=tecumseh+carbe. .......Curt

Glad you showed me these could be had at other places than some of the MB dealers. Have no idea who these 4-stroke carbs are so hard to find for the MB's.

With very little experience with small engines outside of the B&S lawnmowers and MB...never came across these carbs and with some imagination...they might be used if you can't find an MB carb.

 

[curtisfox]

Most snow blowers had them,newer one have fixed jets............Curt

 

[phoobarnvaz]

Most snow blowers had them,newer one have fixed jets............Curt

Being I lived out in NW Arizona for years & when I lived in places which actually had snow...the parents never had the money for a snow blower...but forced us kids out there to shovel the white stuff. The biggest difference...no carb and needing a place to live.

 

[curtisfox]

Same here i fathered 4 sons and also did all the shoveling between us. Even when a kid did it all but now older can't do much. Mow have a tractor with a 42" blower and do my short block and 3 or 4 neighbors ( they like me ). But it is fun and only takes about a hour at the most............Curt

 

[KCvale]

I tried the ~$50 NT carb mod on a new HS 142F and got no performance gain, but a handy fix if you can't find a stock carb and they look cool.
Maybe dinking with the jet will help but not as much and cheap as these.

I tried the ~$10 Iridium plug mod on a virtually identical new HS 142F and the performance gain was staggering!

We have a nice set of terrain around the shop and after it had several miles on it we dropped in the HIX plug and man you can really feel it.
http://www.ngk.com/product.aspx?zpid=9666

I put HIX's in all my 2-strokes, doing it in all the 4-strokes now too.

Last but not least we swapped out the box exhaust for a spare non-EPA 2-stroke chrome exhaust I had.
Again, amazing difference in sound and performance.

If you do one I'd suggest both as together on these last two 29" Fatal Love 7G builds that plug/exhaust combo rocks.

 

[phoobarnvaz]

I tried the ~$50 NT carb mod on a new HS 142F and got no performance gain, but a handy fix if you can't find a stock carb and they look cool.
Maybe dinking with the jet will help but not as much and cheap as these.

That's why I went with the NT setup...rather than trying to order a new 4-stroke carb. Wasn't looking for something to give me outstanding performance...just a way to get whatever parts I may need to actually ride it...rather than the 20 year old car with an ODB 1 connector which is on its last little toe. Being it started and ran...I was more than very happy to be able to ride my pride and joy again. Even more...the looks and inquiries from people who've never seen one before made it worth it. The funniest part is being able to pull into a gas station with almost every pump having big vehicles beside it and me asking for a dollar or two of gas very loudly. Being able to go shopping or to the library 5-10 miles away or drive down a road just because you wanted to see where it went makes it worth it.

I tried the ~$10 Iridium plug mod on a virtually identical new HS 142F and the performance gain was staggering!

We have a nice set of terrain around the shop and after it had several miles on it we dropped in the HIX plug and man you can really feel it.
http://www.ngk.com/product.aspx?zpid=9666

I put HIX's in all my 2-strokes, doing it in all the 4-strokes now too.

Thanks for the link. Just put a new stock NGK plug in when I did all the work last week...especially since I was unsure if gas had gotten into the case when I tried to get it running in June. It's running good...but I will try the HIX when I change it out next year to get ready for the summer.

Do you know of a plug wire which will fit the 142's CDI I can pick up at any auto parts store? Noticed mine's looking a little bit worn...but isn't shocking me. Anyway...a new one...especially a blue or contrasting wire...would be something small...but attention getting.

Last but not least we swapped out the box exhaust for a spare non-EPA 2-stroke chrome exhaust I had.
Again, amazing difference in sound and performance.

If you do one I'd suggest both as together on these last two 29" Fatal Love 7G builds that plug/exhaust combo rocks.

Got a link for one of these? Do they look the same as the stock ones which come with the kits. I've got one of the chrome pipe ones...rather than the box exhaust which comes with some of them. As long as they look the same...might be something I might be interested in looking at to get installed this winter.

On the other hand...I'm having trouble getting the new carb to idle. It will run...but dies if you let off the throttle. When I got it...the "C" on the needle was set in the middle...on the 3rd out of 5 slots. Didn't change it. When I got back from a 10 mile trip yesterday...tried to set the idle by moving the idle screw in & out...but still died. Also attempted to adjust the throttle cable by opening up the adjustment on the top of the carb...but nothing.

With this area being 6000 ft...do I need to move the "C" ring down to the more rich setting to get the carb to get any idle? Am I correct thinking that at this altitude that it's starving for fuel...except for when I have the throttle open?

 

[GearNut]

At higher altitudes it will be starving for air as the air density is thinner up there. Try raising the clip up one notch to lower the needle down further into the fuel jet.
At your altitude you want less fuel blended into the incoming air.

 

[KCvale]

At higher altitudes it will be starving for air as the air density is thinner up there. Try raising the clip up one notch to lower the needle down further into the fuel jet.
At your altitude you want less fuel blended into the incoming air.

Exactly.
Us living closer to sea level lave a higher air pressure, I wonder if a little electric fan on the carb intake would increase the pressure any?

 

[GearNut]

An electric supercharger? Haven't we gone over this topic ad nauseaum?
No benefit would be realized.
One would need to increase the pressure of the atmosphere at 3000 above sea level to create a situation where re-jetting or needle adjustment would no longer be required.

Even if one were to construct a beneficial supercharger, the oxygen density of the atmospheric air entering the super charger's intake would be less than what one would find at sea level.
One would find themselves still needing to tune the carburetor for the altitude at which the engine is to be operated.

 

[KCvale]

That's what I figured too but what heck, threw it out there anyway ;-}

 

[phoobarnvaz]

At higher altitudes it will be starving for air as the air density is thinner up there. Try raising the clip up one notch to lower the needle down further into the fuel jet.
At your altitude you want less fuel blended into the incoming air.

Moved the clip down toward the bowl on Saturday and actually got the engine to idle where it wouldn't before. Will head down sometime this week and move the clip up two notches from where it is now and let you know what happens.

Thank you for the info!

 

[phoobarnvaz]

At higher altitudes it will be starving for air as the air density is thinner up there. Try raising the clip up one notch to lower the needle down further into the fuel jet.
At your altitude you want less fuel blended into the incoming air.

Went down this afternoon after getting home from work. Moved the clip two notches toward the top of the carb to the next to the last notch. Tried over and over to get it started...but tried to start. Would run for about a second then die a couple of times...with black smoke coming out of the pipe. Switched it back again to where I had it before today...the second notch toward the bowl. Still not able to start. Thought my arm was going to fall off.

Ended up letting it sit an hour or so...then tried to start it again...but still nothing.

Got anything for me from here? Know I flooded it...but letting it sit for a while did nothing to get it going. Just put a new NGK plug on it and it was running before...so don't think it's that.

 

[KCvale]

Pull out the plug and pedal it around with the clutch out and no throttle to blow all the crap out of your crankcase.

 

[MotorBicycleRacing]

Pull out the plug and pedal it around with the clutch out and no throttle to blow all the crap out of your crankcase.

His bike is a 4 stroke so the crap in his crankcase would be oil.......and the clutch is centrifugal.

Exactly.
Us living closer to sea level lave a higher air pressure, I wonder if a little electric fan on the carb intake would increase the pressure any?

You gotta be kidding us, I hope?

 

[KCvale]

His bike is a 4 stroke so the crap in his crankcase would be oil.......and the clutch is centrifugal.


You gotta be kidding us, I hope?

Hehehe, didn't catch it was 4-stroke, that's a whole different ball of wax check for a 2-stroke, sorry.

 

[GearNut]

Hmmm... Lowering the needle (raising the clip position) reduces the fuel in the air/ fuel ratio. I am stumped as to how it flooded with a reduced amount of fuel entering the system.
You say you saw black exhaust smoke which indicated an excessively rich mixture. How you got that by lowering the needle position and reducing the fuel mix really has me stumped. How are you working the choke? Fully closed, wide open or somewhere in between?
As for clearing out a flooded engine, letting it sit for an hour should have done the trick.
Removing the spark plug and letting it sit would get it done a little faster. The fastest way is to remove the spark plug and give it about 10 pulls.

 

[Venice Motor Bikes]

You can also start the engine with a socket on a drill motor. (Just remove the pull starter cover.

Here's a link to my video... http://instagram.com/p/tTZafOCnwr/

 

[curtisfox]

Are you getting spark? sounds like you have another problum besides gas...........Curt

 

[phoobarnvaz]

Got out there today before running some errands after work (I walk 6 blocks to work at the school I'm an aide at)...so pulled a few times on the rope and still nothing at all. Actually...it sounded like it was on the verge of starting...but didn't quite have enough "umph" to kick the engine over.

When I get some time on Saturday afternoon...will head down there...put the clip back into the center position (just like when working on a PC...you go back to what was causing the issue before things started going SNAFU)...pull the plug (which is new). Will sit it on the block and pull the rope to see if it sparks. If not...will get the old plug and try the same thing. Chances are...I have a feeling the plug is fouled & the old plug may just start it. If so...I'll know where to go from there. Might even get a good laugh & let one of the neighborhood kids hold the wire as I pull on the rope. Should be great for the video sites to get a few million likes.

As for the choke...before the issues...it was worthless...while not using it...the engine would start. In terms of gas...almost always use premium and had 2/3 or more a tank full when I checked it earlier.

Will also look at the video on starting it with a drill. That way...will save my arm. Got several of these sitting around out in the garage.

Appreciate all of the ideas and steps to get this running. With Winter setting in and a garage I can actually store and work on it out of the elements...it's nice to be able to stay warm when it's freezing outside.