Lauson/Tecumseh H55 Timing

[Zaemo 0]

Where are you guys setting your timing? I have found everything from .035 to .110 BTDC. Mine is set to around .055 to .058 BTDC. The manual I have for an H60 says .050.

My motor starts and runs. It idles fine when it's warm but it's a cold starter. It also should start a little better after it's been sitting only for a short while. Can anyone suggest running more (.080) or less (.050) advance?

Thanks,

Chad

[Coadster32 793]

.055 to .058 is fine. For that motor anywhere between .045 and .055 should work just fine. I haven't really noticed a difference either way. Just remember those carbs are really touchy.

[MikesRJ 552]

These two Service Manuals might help:

http://www.mywheelhorse.com/graphics/file/...vice-Manual.pdf

http://www.mywheelhorse.com/graphics/file/...ecumseh_BSI.pdf

[DMK855 15]

Chad, my HH60 is set a .032 and seems to work just fine there. Hot or Cold. It does have a brand new carb. though as well!!

Can't help you on the H55 timing, but mine too, is a little tough to start at times.....

Good Luck!!

Dwayne

[1961551 2]

hi, let me tell you, ive been there. youre h55 will not run right unless its @.080 btdc. i did not have the tecumseh piston adapter, so i had to pull the head. not a big deal. i assume you have a dial indcator. set it @ .080 btdc. keep checking to make sure you have .020 point gap. you neeed a continuity box. or a dvm with a beeper to do this. its time consuming. but in the end its rewarding. people hate tecumsehs because they cant them to run right. but the h55 is a good engine. pm me if you need any help... jimmy

[DMK855 15]

A little off topic, but according to the manuals Mike posted my timing on my hh60 is way off....... Appears it should be .080 as well..... Sorry for getting off topic Chad!!

I do have a quick question though!! Are you using points or a module ?? The old tech's don't work with the module!!!

[SkyhawkTL 19]

Chad

Your engine should have an internal coil running with 2 flywheel magnets as I understand it. This system is basic and dependable. If you have only 2 magnets, you could try a module to replace the mechanical points - but the point system is good.

If your setup has three coils and many magnets then you have a charging system and a module won't work with them. This system has to be right on for a hot spark. Not hard - it just takes time.

For my recent Tecumseh build I dial indicatored "correct" timing - and then "piston stopped" to locate exact TDC. Both marks are visible when running.

I found I could advance or retard on either side of correct and the engine ran well.

(Ever see an old outboard motor running? My 1938 evinrude has no throttle plate - the poppet carb is wide open all the time - the PRM is changed simply by going tons retard or tons advance.) I'm currently running a lot of advance on my Tecumseh just because thats the way I like it. My point is - there is room to play here.

My thought on Tecumsehs is they like good compression. Get the ignition to produce a hot spark first, then time it to the specs shown in this thread.

Finally - the carb is just like everyone has posted in this thread;

"seems to work just fine there. Hot or Cold. It does have a brand new carb"

"Just remember those carbs are really touchy" A clean set-up carb with no vacuum leaks will sing all afternoon. Good luck.

[Coadster32 793]

This morning when I responded, I was at work and threw out what I thought I remembered from my H55 build over the past summer. After coming home from work and reading some of the other replys, I thought I'd dive back into the book.

The H55 motor is in colum #9. I got that info when I actually measured the bore and stroke of my engine when the head was off. (easy to do)

This picutre shows a closer look. The verticle and horizontal versions both have the same timing. Even if you have a 5Hp or a 6hp, the timing is still the same. I once had a 4hp tecumseh motor that was .010 off timing, and it wouldn't run. I set my H55 right to .050, and it purred like a kitten. Whatever you do, good luck.

[Zaemo 0]

Hey Guys,

It seems that the general consensus is around .080. I have the engine running, and it seems to be decent. However, I won't be able to leave it alone. It started today pretty well with half choke and a little throttle. Like I said, I'm at a little under .060. It actually idles fine when it's even a little warm but it doesn't start as well as I think it should after it's been off for a short time.

I did make a separate mark on the drive side at .080 so I shouldn't need to take the head off again. I don't have a dial indicator but I did figure out how to do the points with my VOM.

If I had the head off once, would I absolutely automatically need to replace the head gasket no matter what?

Oh yeah, I have the charging system style w/ 3 coils.

Z

[Zaemo 0]

See, that looks like my book. .050.

Z

[Coadster32 793]

I just checked out Mike's links, and don't know what to say. The stroke and bore lines up to be .090/.100 BTDC. I'm very interested on what works well for you.

A little off topic, but according to the manuals Mike posted my timing on my hh60 is way off

I would think that if the HH60 needed to be .080, and was set at .032, it wouldn't fire at all?? :thumbs:

[1961551 2]

it will run at .050 and run well. if you put it under a load , it will not. i tried to find the specifications and could not at the time. i set mine at .055. it ran well at idle and took throttle under no load. under a load is a different story. no power. like pulling a camper... im telling you from experience, set it at .080 btdc. with point gap at .020 thats all to the ignition part, but make sure your carb is clean. pm me if you you have any questions.

jimmy

[Zaemo 0]

Thanks Jimmy,

I think that I'll take your advice on that. If it runs worse then we'll have some more to talk about. It makes sense that more advance would help at higher RPM as there is no mechanical advance so one would have to build it into static timing. I'll change it and report back. I may need to get that dial indicator after all. It's a good thing I don't hate buying tools!

Z

[DMK855 15]

A little off topic, but according to the manuals Mike posted my timing on my hh60 is way off

I would think that if the HH60 needed to be .080, and was set at .032, it wouldn't fire at all??

Coadster...... I too am a little confused. It does act a little sluggish under load. This might explain why. The info I was given was for the Techy motors on the Rupp minibikes!?!?! It got me running, but now I want to dig back in and see if it helps!!

[Coadster32 793]

I'll be following this post closely for sure. If all dives into their motors, I'd like to hear the end results as well. As far as my book and information, that's all I've used in the past with great results. The minibike I had was a 4hp, and handled the load awesomely. The 551 I have, isn't a worker, but runs well under all coditions, and throttle positions.

The info I was given was for the Techy motors on the Rupp minibikes!?!?!

I don't really see the difference on the use of the motor as far as that goes. They just used a different mounting plate on the carb beacause the motor is set on a slant.

im telling you from experience

Very hard to argue, and thankful for sharing. New light shed is a wonderful thing, and I'd be an idiot to ignore it. It also is in line with the literature that Mike supplied. Again to Mike,

make sure your carb is clean.

I totally echo that statement. :banghead:

[wheelhorse656 20]

i have always set them at 48-50 thousenths they run there best there :banghead:

[1961551 2]

were talking about 50 year old engines. alot of hands could have been on these engines. my point is, there are at least 3 different point cams that will fit these. the point cam slips onto the crank. there are substantial changes in timing when these are changed. i think mine was original, but i cant be sure. im 35, the engine is 50. what i do know is, mine would not run right at .055 btdc. it is right at .080 btdc. with another point cam, .050 may be right. i have two more cams and didnt try them at .050. sorry for more confusion, but i just remembered this, and i think its fairly important. i wish i could tell you which one is which. i had to learn the hard way. jimmy

[Coadster32 793]

there are at least 3 different point cams that will fit these

That would certainly explain alot. Besides the hard way , I wonder if there's an easy way to tell which one might be in our engines. :thumbs:

[Zaemo 0]

As far as the cam goes, the spark happens in relation to the position of the piston regardless of what the cam looks like, correct? There is no dwell or any other adjustment other than the gap which everyone agrees is .020. The points are open or closed and fire when we tell them to.

I have a brand new carb that I bought for another sears/tech motor. I assume it's still correct despite the 5000 different part numbers. I'll get some pics up today also.

[1961551 2]

As far as the cam goes, the spark happens in relation to the position of the piston regardless of what the cam looks like, correct? There is no dwell or any other adjustment other than the gap which everyone agrees is .020. The points are open or closed and fire when we tell them to.

I have a brand new carb that I bought for another sears/tech motor. I assume it's still correct despite the 5000 different part numbers. I'll get some pics up today also.

There is no dwell or any other adjustment other than the gap which everyone agrees is .020

you are correct. timing is set with piston location/points open. there are no other manual adjustments. however, the point cams are different. i will dig them out and post pics if i can find them. one has an abrupt flank. (short duration) one has a long flank (points open slower) they are also timed different (keyways) i dont know why yet. i do know a have two h55 engines and they have different point cams with this being said, an engine will still fire when the points open. reguardless of how slow or fast. if some was to change the cam and points, this would affect one jimmy

[SkyhawkTL 19]

As far as the cam goes, the spark happens in relation to the position of the piston regardless of what the cam looks like, correct? There is no dwell or any other adjustment other than the gap which everyone agrees is .020. The points are open or closed and fire when we tell them to.

I have a brand new carb that I bought for another sears/tech motor. I assume it's still correct despite the 5000 different part numbers. I'll get some pics up today also.

Great Discussion - and some sharp mechanics - this place is great.

The spark happens when the points open, and the primary side collapses.

The points open when the point cam tells them to - and it is keyed to the crank. Different cams = different open times.

There are different point cams that will open the points sooner or later and you have to have the correct cam for the magneto style you are using - 1 coil or 3 coil.

Imagine a line through the mounting holes on the 1 coil mag - see how the ignition coil is approx. 90 degrees - but the ignition coil on the 3 coil mag it is not. 2 mags = 2 point cams.

The mag mounting slots give you the room to "Time" the points.

In addition - some no spark is actually just very weak spark, and that can be caused by weak magnets.

[Zaemo 0]

Well Fellas,

Here's the preliminary verdict.

I love it. I adjusted the timing as close as I could to .080 (between .078 an .080). I ran out of room on the adjustment. Perhaps I could use a cam that opens earlier??? I have the version with 3 coils like your second magneto picture Skyhawk. I remember you saying you like a lot of advance also, correct?

More advance makes sense as per earlier adjustment. Why else would your old car have a mechanical vacuum advance? It helps. So far, restarting the engine is easier. It starts almost immediately, like it should when it's warm. Idles well so far also.

Climbs up my steep driveway also. Needs RPM but that's to be expected.

I took it up the street quickly and it didn't bog down nearly as much going up the gradual incline. Now I'm not so worried about the governor. It seems to stay at speed easier. We'll see when I get a chance to put the twins in the wagon behind it. Too cold for them to try tonight. Seems like it will be way less throttle adjustment to keep within my selected powerband.

If anyone else wants to give it a shot, I would highly recommend it. It might keep you in practice also or give you an opportunity to change those points you've been thinking about.

I'll try again later to be sure.

Thanks and I hope this ends up being the end all be all timing thread for anyone else who needs help.

It's been sitting for 10 minutes. I'm going to go try it again.

Now I just have to figure out why I get oil coming out of the vent hole on the valve cover.

Chad

[1961551 2]

Now I just have to figure out why I get oil coming out of the vent hole on the valve cover.

glad youve got it running better. makes a huge difference to have them right. as far as the oil. its usualy 1 of 2 things. overfilled with oil being 1. number 2 being the baffle plate is installed upside down.

[DMK855 15]

Oh boy..... Different point cams.... Didn't even cross my mind!! Looking forward to the pics of them. That sure adds a whole other side to this thread!!

[DMK855 15]

Chad,

Glad you have it up and running better!! Going to have to bring it over sometime and check out my "projects"!!

Dwayne