149 Running terrible after overhaul

[bwstevens]

I have seen five engines run just fine with the crank broke clean through between the cam gear the first or only rod throw . None of these suggestions helps this fellow out with an engine that run fine before being rebuilt.

 

[abthomas]

I've had some junk points that came with a kit or someone cranked on the screw the holds the wire tight till they have it stripped and the wire is making intermittent contact at a higher rpm, if it ran before the rebuild then it will run again ,and when you find it likely it will be something simple overlooked !

 

[Mark Evans]

Could be as simple as putting a timing light on the coil wire and start and watch the light as it throttles up and back down if your are using a self battery powered light it will show if it’s lost or weak on spark it shows up in a weak light !!!!

 

[jstouffer]

Did not mess with it over weekend. Will probably get back to it tomorrow and will let everyone know what I find or do. Thanks Guys

 

[jdrong]

A few years ago a friend asked me if I would rebuild his Harley two cycle golf cart engine since he knew I had experience with doing that. I rebuilt the engine, did the usual prestart checks, like timing and points gap, etc. and noticed new points and condenser, everything seemed ok. It started and idled well. A road test proved different thought, if misfired and backfired among other things. Finally out of desperation I reinstalled the old points and condenser that was left in the cup holder and it ran great. A valuable lesson learned by me! I suspect the points and condenser were cheap foreign knock-offs.

 

[jstouffer]

Well put on and started with New Carburetor runs the same idles smooth when you accelerate misses and spits out the Carburetor. Put on old points no difference. Checked fuel flow. Any other suggestions fellows.

 

[Bret McFarland]

Well put on and started with New Carburetor runs the same idles smooth when you accelerate misses and spits out the Carburetor. Put on old points no difference. Checked fuel flow. Any other suggestions fellows.

Sounds like ignition. I wonder if something could be grounding out under load? Had a '69 Camaro with cheap plug wires, same symptoms -- was cross-firing.

 

[Doug Rusk]

You need to try more than just old points. Condensor can do weird stuff too. If that ain't it it sounds like possibly slow timing to me at a wild guess. I mean if everything else checked out already.

 

[lpalma]

Are all the head bolts tight? Check the points wire for cracks, remove the the points cover and run it with it off, see if the points open and close. How about some pix of your engine, carb, coil and such. We may see something amiss...

 

[Mark Evans]

Try self powered timing light and watch for intermittent light(loss of power) or light getting weak loss of proper voltage !!!!????!!!!

 

[mgonitzke]

Well put on and started with New Carburetor runs the same idles smooth when you accelerate misses and spits out the Carburetor. Put on old points no difference. Checked fuel flow. Any other suggestions fellows.

Did you static time the points or use a timing light to get the timing correct? As has already been said several times, you can't just set them to 0.020" and expect it to be perfect.

Assuming no issues with condenser, plug, or plug wire, this is almost certainly because the timing is advanced or the intake valve clearance is too tight.

 

[Mark Evans]

Engine is an engine, spark, fuel, air, timing !!!

 

[jlord]

Checking the condenser is pretty easy. I would do that for sure to try and rule it out. Disconnect it for this test.

Take an old school type VOM (volt-ohm-meter), one with an actual needle type meter movement (because they work best for this) and set it in the ohms position at R-x100 or x1000. Connect the leads one direction and you should see the meter needle "pulse" and then decrease to infinity as it charges. Then remove the leads and set meter to 10 volt DC and touch again. You should see the needle deflect and then go to zero. If you do not get these results, try reversing the leads on both tests.
These are pretty simple capacitors that are non-electrolytic, meaning that they are, I believe, like an A/C capacitor and not polarized and usually of a dry type.
If from a quality manufacturer, they are pretty robust and last a very long time.
This is not a definitive test, but will see if it is shorted or has too high of a resistance level.
If you have a more advanced meter, they often have a capacitance testing function.
I myself have a dedicated capacitance testing meter that I use for motor, power supply and electronic caps, but they can be pricey. They however will give you the value in micro-farads of the cap which can be compared to the manufacturers value.

 

[Mark Evans]

Remember the machine rule kiss along with air, fuel, spark, timing there is flow I have had times when people had worked on hydraulic and not plugged the caps on while fixing and have debris in lines can happen to intake tubes and exhaust lines have had muddobbers plug up mufflers, and intakes too, kiss, look over all the tubes for flow restrictions !!!!!!!

 

[jdrong]

Well put on and started with New Carburetor runs the same idles smooth when you accelerate misses and spits out the Carburetor. Put on old points no difference. Checked fuel flow. Any other suggestions fellows.

But, did you try a different condenser?

 

[eweiss]

Did I miss something? Doe's the engine idle fine , then miss just revving it up, or underload with the cub moving? If this happens moving then there's another problem

 

[jstouffer]

Yes engine idles fine then misses as you try to accelerate throttle. Have not checked condenser yet, but will in next day or so and let everyone know. Cannot static time engine because cover does not have hole in it. Bought this 149 about 15 years ago previous owner had replaced original engine with new Kohler engine. Only reason i pulled apart was governor gear broke was still running fine. Just no way to control rpm.

 

[lpalma]

The hole may have a plug over it or the starter is in the way.

 

[jlord]

Remember the machine rule kiss along with air, fuel, spark, timing there is flow I have had times when people had worked on hydraulic and not plugged the caps on while fixing and have debris in lines can happen to intake tubes and exhaust lines have had muddobbers plug up mufflers, and intakes too, kiss, look over all the tubes for flow restrictions !!!!!!!

( kiss = Keep It Simple Stupid ) ?

 

[ffgosda]

I’m not very experienced in these things yet, but is there a possibility it could have something to do with the compression release not working right?