Tecumseh sputter, worse under load!

[Team70R 157]

Still can't get the lawn ranger dialed in.. got the new Chinese carb on and it's doing the same thing before I replaced it. The high idle screw seems to have no effect most of the time! I cleaned the valves and am picking up a set a feeler gauges tomorrow. just when it seems like it's dialed in it will start to sputter and smoke again! What next!??

[oldredrider 2,549]

Timing of spark can be touchy on Teccys. Almost gotta be dead on to spec for them to run righr.

[Team70R 157]

I know the whole ignition assembly will "rotate" to adjust the timing but how do you check it?

[formariz 11,988]

Does it idle OK and then sputters when in high RPM or load?

[Coadster32 793]

Lat time I did a Tecky motor, the head was off, and I depth checked down to the top of the piston when the points open. There is a chart someplace to tell you this. Normally, it works perfectly after that, (the spark that is). Perhaps also your condencor might be on it's way out. Just some thought.

[Team70R 157]

7 hours ago, formariz said:

Does it idle OK and then sputters when in high RPM or load?

I wouldn't say it idles perfect but it does seem to run better at lower rpm. If I push the the throttle all the way in it dies.. when I pulled the head again last night it was all wet with what appeared to be oil!?

[formariz 11,988]

You may have a weak spark and need to replace your condenser. While at it check your points perhaps just need a little cleaning. Set gap to .020. If you replace the points setting the timing is a bit more involved on that one, you should remove cylinder head to make sure when you do it that piston is in the right position. I would stay for now with cleaning points and replacing condenser.

 

Possibly needs rings  if there is oil in the head, but I had one that would have a lot of oil in head but still run well (with smoke of course). Take a photo of piston top if you did not clean it. From that we can tell if it is bypassing oil through rings.

[Team70R 157]

I just put in a new condenser last night and inspected the points. They are clean! Just a little dust in the area.. Gonna measure the gap tonight. I already cleaned the  head and cylinder. It looks great and free of gouges and scrapes! I did check the compression and it came back around 60-70 psi

[formariz 11,988]

File the points' contacts just a little to remove oxidation. Dust on the other areas does not make a difference. Don't loosen stator bolts, you may change timing . If it starts it may be ok for now. 

[Team70R 157]

6 minutes ago, formariz said:

File the points' contacts just a little to remove oxidation. Dust on the other areas does not make a difference. Don't loosen stator bolts, you may change timing . If it starts it may be ok for now. 

I just checked the points gap and it was way too short! Set it to .020 and putting it all back tougher now

[Tim.0 39]

If its a 4 stroke I am wondering why there is oil going up into the head. I am not familiar with that engine though. DId you try a wet and dry compression test? Maybe I am way off base.

I hope it works for you changing the point gap.

Edited June 1, 2017 by Tim.0

[Team70R 157]

Well changing the points gap didn't have any effect at all .... gonna try the wet/dry test i guess 

 

[oldredrider 2,549]

Last summer I had a similar problem on a Lawn Ranger engine. I think it was an H60...(a LOT of motors have been on my bench).

Exhibited the same symptoms. Was running fine for my friend, made a noise and just wouldn't rev up smoothly or run at a high rpm without coughing and sputtering. Tore it down and speced everything. Set points, timing, valve lash etc. Stumped. Sent it to another motorhead and he was stumped too.

After pulling the flywheel for the last time to double check points and timing, I put on a different flywheel because it was the only thing I hadn't changed.

Hit the key, it fired right up and ran smooth as silk.

My theory is the steel insert in the aluminum flywheel had turned slightly throwing the timing off.

A year later and it's still running fine.

Just want to throw my experience out there.

[Team70R 157]

1 hour ago, oldredrider said:

Last summer I had a similar problem on a Lawn Ranger engine. I think it was an H60...(a LOT of motors have been on my bench).

Exhibited the same symptoms. Was running fine for my friend, made a noise and just wouldn't rev up smoothly or run at a high rpm without coughing and sputtering. Tore it down and speced everything. Set points, timing, valve lash etc. Stumped. Sent it to another motorhead and he was stumped too.

After pulling the flywheel for the last time to double check points and timing, I put on a different flywheel because it was the only thing I hadn't changed.

Hit the key, it fired right up and ran smooth as silk.

My theory is the steel insert in the aluminum flywheel had turned slightly throwing the timing off.

A year later and it's still running fine.

Just want to throw my experience out there.

I just ordered a new coil! Hopefully that takes care of it. Everything else is new. I've given up on a couple Tecumsehs in the past but I'm not gonna quit on this one!!

[oldredrider 2,549]

Maybe I'm stubborn...or stupid! I won't let an engine get the best of me. This Teccy taught me a few things. Good luck with your quest for a solution.

[Team70R 157]

Thanks old red!!

[6bg6ga 272]

19 hours ago, formariz said:

You may have a weak spark and need to replace your condenser. While at it check your points perhaps just need a little cleaning. Set gap to .020. If you replace the points setting the timing is a bit more involved on that one, you should remove cylinder head to make sure when you do it that piston is in the right position. I would stay for now with cleaning points and replacing condenser.

 

Possibly needs rings  if there is oil in the head, but I had one that would have a lot of oil in head but still run well (with smoke of course). Take a photo of piston top if you did not clean it. From that we can tell if it is bypassing oil through rings.

 

I will disagree with the replace the condenser idea until you check it using one or two possible methods. If your meter has a cap check function use that and if not set your meter on high ohms and do the test procedure I outlined in another thread.

 

1.) Remove the condenser from the engine (or at least disconnect the lead wire). Note the small metal connector located on the end of the condenser. This connector is the "hot" or power connection. The metal case of the condenser is the grounding point. Discharge the condenser by shorting the lead wire to the case.

2.) Switch the meter to the ohms position. Place the red lead into the "ohm" connector on the meter. Insert the black lead into the "com" or common connector on the meter. Set the resistance range to the highest available setting (if it is selectable). Connect the test leads together and zero the meter. If the meter won't zero replace the battery. (Yes, an ohm meter has a battery).

3.) Touch the red lead to the hot connector on the condenser. Place the black lead to the metal case on the condenser. The meter's needle should jump slightly to the right (toward 0-ohms), then should drop back to the left towards infinite resistance). Hold the leads in place for 15 to 20 seconds. This action places charge in the condenser. If the test shows any reading other than infinity, the condenser is leaking and needs to be replaced.

4.) Remove the leads and reverse the placement to the condenser. Move the red lead from the hot connector to the metal case, and move the black lead from the metal case to the hot connector. At the moment where both leads are touching the correct points, the meter should jump towards the right. The second time the needle may move twice as far, as this action discharges the condenser. Holding the leads in contact should again result in movement of the needle back toward infinite resistance.

5.) Movement of the meter's needle indicates the condenser is good. If no movement was indicated on the meter in any circumstance, the condenser is bad and must be replaced. Retest the condenser several times for a consistent reading.

In operation the condenser will "ring" at up to 300 volts, so the condenser needs to be rated much higher, no less than 600 volts DC. The ignition will likely work with any capacitance value between 0.05 and 0.6 microfarad. Too high or too low value may eventually transfer metal from one side of the contact points to the other side leaving a pit and a point. Capacity of spark coil capacitors ranges from 0.2 microfarad to 0.33 microfarad. Almost all automotive coils use a 0.25-0.29 microfarad capacitor.

 

Removing the condenser just because you don't know what to do is not a good practice. Checking the capacitor FIRST is an established trusted method of troubleshooting and repair.

 

 

If it ain't broke don't try to fix it. If the cap is good substituting and unknown WILL cause the points which weren't burned before to burn and or pit. Removing the cap and running it is NOT an acceptable method of troubleshooting.  

Edited June 2, 2017 by 6bg6ga

[formariz 11,988]

Just hang in there. Tecumseh's are finicky and hard to get going right, mainly because many of us are not used to deal with them. Lets see after you change coil. If you can take a video with sound of it running. It also sounds like it may be running in a sort of flooded condition. Hard to say without hearing it. Does it have a fuel pump? As for replacing condenser and points that is done as a maintenance item any way.It is not going to make run worse. I do that to every engine I get and I have well over 20 all running perfectly. Testing is fine and should be done , however I have also tested some bad ones that test good and good ones that test bad. Not everyone has the knowledge or the capability to do such testing.Those items are not expensive anyway.

Edited June 2, 2017 by formariz

[Team70R 157]

It is just a gravity fed fuel system. I'm trying to upload a video 

IMG_2408.MOV

Let me know if you can't watch if

 

[formariz 11,988]

I see it. Firing is inconsistent. I think it's time to check timing and to make sure that there are no shorts under flywheel .  Did you say you got a new coil? 

[Team70R 157]

4 minutes ago, formariz said:

I see it. Firing is inconsistent. I think it's time to check timing and to make sure that there are no shorts under flywheel .  Did you say you got a new coil? 

Put in a new set of points and condenser right after I took the video. Still doing same thing so I've got a new coil on the way. Will be here tomorrow. I already unhooked the ignition switch wire to eliminate that as an issue 

[formariz 11,988]

So the video is before changing points and condenser ? You have not tried it after or did same thing?

[Team70R 157]

Oh I tried it after. Pulled the plug and grounded it on the head. Sparks very sporadic! Put in an old coil that I had and had no spark at all.. 

[formariz 11,988]

OK, so lets put the coil in since you got it anyway perhaps new plug too. I will post instructions or a link on how to set timing on that one when I have a little more time unless someone else does it before me. Hang in there, it starts and runs although badly so that is already more than half of the battle.

[Team70R 157]

Gonna grab a new plug this weekend and get it all back together Monday! That would be awesome if you can get me some timing info!