Can't get model hot and miss engine to start?

[SmallHaul]

With Jasonb's help i have figured out that i have an Associated hired man engine made from a breisch kit. I cleaned the points and have great spark. I am using coleman camping fuel. I am using a 5 cell nimh pack (6v) to power the coil

It will not start..i noticed two things that don't seem right..

One is the coil is getting hot? Why would it get hot?

Two i noticed while trying to start it that the spark was jumping from the tip of the plug to the metal base so, i changed the way my clip was on it and fixed that problem but, the plug gap is a much shorted distance than the plug tip to the plugs base so, i am not sure why the spark would want to jump that longer distance instead of the end of the plug that is inside the engine?

The other question is which way is the engine supposed to run? From watching people start this engine on youtube they always stand behind the engine and pull the flywheels down to start it so, looking from the left side of the engine it is running clockwise is that correct?

 

[Jasonb]

A spart will jump easier in open air than under compression in the cylinder.

Thats the way they turn, clockwise when viewed from the side with the cylinder to the left.

I find with a lot of hit & miss engines that you hardly need to open the needle valve otherwise they can flood, just crack it open 1/8th of a turn to start with. You may need to prime it first by putting your finger over the air inlet and turning over once or twice to suck up some fuel.

J

 

[rklopp]

Does the engine fire at all? If not, and spark is OK, then the problem is fuel. I find my Hired Man easiest to start if I take off the "air cleaner" so that I can choke the mixer with my fingertip. If you don't have a check valve in the fuel line, the fuel will run back to the tank between firings.

 

[chrispare]

I have a hit miss and tried running Colman fuel and it would not fire either. Switch to regular gas and it'll fire right up. Even if I start it on gas and switch it won't run on Colman.

Chris

 

[SmallHaul]

One thing about the tank that doesn't make sense to me is the small vent tube goes all of the way to the bottom of the tank? Why would it be made that way?

A spart will jump easier in open air than under compression in the cylinder.

Thats the way they turn, clockwise when viewed from the side with the cylinder to the left.

I find with a lot of hit & miss engines that you hardly need to open the needle valve otherwise they can flood, just crack it open 1/8th of a turn to start with. You may need to prime it first by putting your finger over the air inlet and turning over once or twice to suck up some fuel.

J

So, when it sparks outside the cylinder that is ok and it isn't telling me i have a spark plug or grounding or other problem?

I think you might be right with the needle valve setting because i tried closing the needle all the way in and i started at 1/2 turn and went 1/4 turns from there and then i flooded it twice.

Does the engine fire at all? If not, and spark is OK, then the problem is fuel. I find my Hired Man easiest to start if I take off the "air cleaner" so that I can choke the mixer with my fingertip. If you don't have a check valve in the fuel line, the fuel will run back to the tank between firings.

Yes, a couple of times it fired and ran for about six or seven hits and stalled. The little wood sled that it is mounted on sure doesn't have enough weight to keep the engine from jumping around on the table. I was using two fingers to choke it but, the more i think about it i think i was pulling to much fuel in.

Where could i purchase a small check valve for it?

I have a hit miss and tried running Colman fuel and it would not fire either. Switch to regular gas and it'll fire right up. Even if I start it on gas and switch it won't run on Colman.

Chris

I am going to try and fire it up again this afternoon and i will try gasoline first and see if it helps.

 

[Jasonb]

Looking at the photos you posted the other day you should not need a check valve as the tank is above the carb, only really needed if tank is below the needle. More likely its flooding due to the high tank

 

[SmallHaul]

Looking at the photos you posted the other day you should not need a check valve as the tank is above the carb, only really needed if tank is below the needle. More likely its flooding due to the high tank

Jason, you were right i had the neelde way too far out..it runs nice about 3 or clicks open.

Now that i have it running i have even more questions, lol.

[ame]https://www.youtube.com/watch?v=gZAbFAKbPxM[/ame]

After getting it running well on gasoline i tried the coleman fuel again and it ran ok on the coleman fuel but, it did not run as well...during the hit cycle it would often hit twice instead of once and when run on the gasoline it was a very constant single hit every time..is it running too rich when you get multiple hits when it fires?

 

[Jasonb]

The colemans is a lower octane content so does not give quite the "bang" that you get with pump gas so that may be why it runs better on that. Can depend on compression as well.

Yes need to get ir running a bit slower now as its firing on almost every cycle Oh and get that green paint changed to Red so it looks like an Associated engine

I'm not sure if its the position of teh camera but the engine looks a bit larger than I thought, what is the flywheel diameter, the Hired Man you mostly see has 6.25" ones.

 

[SmallHaul]

The colemans is a lower octane content so does not give quite the "bang" that you get with pump gas so that may be why it runs better on that. Can depend on compression as well.

Yes need to get ir running a bit slower now as its firing on almost every cycle Oh and get that green paint changed to Red so it looks like an Associated engine

I'm not sure if its the position of teh camera but the engine looks a bit larger than I thought, what is the flywheel diameter, the Hired Man you mostly see has 6.25" ones.

I have the governor weights set as loose as they will go and it still runs too fast. I was using a smooth piece of the metal to "cheat" the governer while running and will very slowly without stalling. What is the best way to get the weights out sooner? Do i need to make heavier weights? Is there some other adjustment that needs to be made?

It is the position of the camera..the flywheels are about 6 inches in diameter.

It seems really out of balance..the only reason it seems some what smooth is because it is zip tied to two 10 pound dumb bells. It shakes very badly.

Is there a way to balance it? I guess you would have to remove the crank, rod and piston and balance the whole assembly?

 

[Jasonb]

You could take a look at the governor linkages, there is usually an adjustment on the latch which adjusts when the rod is held, this may not be engaging correctly though on the hored man I think its fixed.

Also make sure the governor arm is moving close enough to the push rod that it can engage against the small pad on the side, there is a knurled screw that adjusts a spring, slackening that off will allow the arm to move closer to the rod. The spool needs to be able to slide far enough along the crakn when the weights fly out, if the flywheel is a bit too close you may not be getting enough movement.

Some engines are a bit livelier than others and will jump about a bit. rather than have it on a foam pad clamp the sled directly to a solid bench. Try zip tieing some lead to the flywheels to see if that improves things, once you find out where its needed fix it permanently and blend in with bondo so it looks like part of the casting, or drill out the flywheel rim opposite where you add the lead.

 

[SmallHaul]

You could take a look at the governor linkages, there is usually an adjustment on the latch which adjusts when the rod is held, this may not be engaging correctly though on the hored man I think its fixed.

If i understand what i am looking at..it is adjustable and the way it is set right now it just has enough room to engage when needed...maybe i should adjust it so that there is 1mm of clearance for the foot to engage more easily?

Also make sure the governor arm is moving close enough to the push rod that it can engage against the small pad on the side, there is a knurled screw that adjusts a spring, slackening that off will allow the arm to move closer to the rod. The spool needs to be able to slide far enough along the crakn when the weights fly out, if the flywheel is a bit too close you may not be getting enough movement.

When it is fully engaged there is still clearance between the flywheel and the spool so that is ok.

Some engines are a bit livelier than others and will jump about a bit. rather than have it on a foam pad clamp the sled directly to a solid bench. Try zip tieing some lead to the flywheels to see if that improves things, once you find out where its needed fix it permanently and blend in with bondo so it looks like part of the casting, or drill out the flywheel rim opposite where you add the lead.

I used a small spring to hold the exhaust valve open so that i could spin it using a model airplane started with a rubber wheel on it and i tried adding weight on the existing flywheel weights and i tried adding weight opposite the built in flywheel weights it never seemed to smooth out or make much difference? It seems like if you spin it too fast it starts to shake a lot. Maybe when i get the speed way down it will be smoother as is...?

 

[rklopp]

There is no way to balance a single-cylinder engine. The best you can do is a compromise. If you balance the weight of the piston and conrod at TDC, you will be kind of balanced at BDC (off due to the difference in acceleration across TDC vs BDC), but you will be way off at the 90 and 270 degree positions because your counterweights will be too heavy for those positions. There is a rule of thumb, which I forget, but it might be something like counterweights should be 1/3 the weight of the piston and conrod together. There are more sophisticated schemes involving weighing the big end of the conrod alone, but probably not fruitful for a farm engine.

 

[SmallHaul]

There is no way to balance a single-cylinder engine. The best you can do is a compromise. If you balance the weight of the piston and conrod at TDC, you will be kind of balanced at BDC (off due to the difference in acceleration across TDC vs BDC), but you will be way off at the 90 and 270 degree positions because your counterweights will be too heavy for those positions. There is a rule of thumb, which I forget, but it might be something like counterweights should be 1/3 the weight of the piston and conrod together. There are more sophisticated schemes involving weighing the big end of the conrod alone, but probably not fruitful for a farm engine.

Thank You very much for the information that is interesting and makes sense.

I messed with the timing and the governor settings a lot tonight and got it running very slowly. It does run much smoother when you get it running slower.

Funny thing happened tonight, i would get the timing set and play with the mixture to get it running just right and then after running for a few minutes it would change and stall or speed up...and i also kept hearing a metal sound when it fired like there was slop in the connecting rod or something so i searched around looking for slop and found that the left flywheel was loose and that was changing the governor setting every time it would move around, lol. So i had to lock the flywheel back into position and fuss with it to get the governor right again. It is running really nice now i'll get another video up soon.

 

[SmallHaul]

Here is a video of how it is running now. It is running on white gas with a little wd40 mixed in with it. I am very happy with it now. It doesn't shake very much at all now that it is running much slower. Now i need to make nicer heavier oak bas for it house the battery and switch.

[ame]https://www.youtube.com/watch?v=D8A6axildSM[/ame]

 

[SmallHaul]

[ame]https://www.youtube.com/watch?v=X3Mss1dJu04[/ame]

 

[Jasonb]

Thats running better now, another advantage of the less explosive colemans fuel.

 

[SmallHaul]

Thats running better now, another advantage of the less explosive colemans fuel.

Thanks Jason. I appreciate all the help.

Thanks everyone for all the help you gave me to get this engine running well!