1965 tecumseh h25

[loudog54]

Can anyone help me with the ignition timing of my engine ? i'm not sure if it's 0.065 or 0.035 BTDC thanks

 

[markus]

Can anyone help me with the ignition timing of my engine ? i'm not sure if it's 0.065 or 0.035 BTDC thanks

H25's in my books and Tecumseh literature dating back to 1983 show as .065 btdc (remember if you don't have you points correctly set beforehand your timing will be off no matter if your gauge reads correct).

H35 though, Tecumseh changed their tune in the literature...Literally! In the older publications and service/reference posters I have they show Horizontal H35 engines as being set @ .035 but Vertical versions @ .065 up into the 1980's but in my 1988 later books in my collection they just read as .065 across the board. I tried a few years ago when I noticed the difference in books to see if any old school technicians had an answer or maybe a service bulletin etc.. as I always set them a .065, but nobody seemed to know or answer so its still a head scratcher for me, I still find the .065 to be a better setting, at least with 1970's era parts.

 

[loudog54]

Thanks Markus . Ihad the timing at .065 and could not get it started. When i put it at .035 it started and ran good but is not starting when warmed up. I've changed carbs same thing i'm thinking that 80 psi is the reason?

 

[creia]

Thanks Markus . Ihad the timing at .065 and could not get it started. When i put it at .035 it started and ran good but is not starting when warmed up. I've changed carbs same thing i'm thinking that 80 psi is the reason?

It should still run OK on 80 PSI compression. When you checked compression did you hold open the throttle plate completely? (if not your reading will be lower)
Michael

 

[loudog54]

It should still run OK on 80 PSI compression. When you checked compression did you hold open the throttle plate completely? (if not your reading will be lower)
Michael

No i didn't i'll try that .

 

[markus]

While I have never had a an H25 apart that is that old, Most of the small frame H engines mid-late 1960's had a compression bypass hole in the valve seat. That was the "ezee-start" as noted on the balloon decaling. So compression tests are misleading on these as well as many other small engines due to most of them having a some sort of compression relief.

I stuck a carb cleaning tip through the hole in this 1968 H35 I am rebuilding right now as an example:

 

[loudog54]

While I have never had a an H25 apart that is that old, Most of the small frame H engines mid-late 1960's had a compression bypass hole in the valve seat. That was the "ezee-start" as noted on the balloon decaling. So compression tests are misleading on these as well as many other small engines due to most of them having a some sort of compression relief.

I stuck a carb cleaning tip through the hole in this 1968 H35 I am rebuilding right now as an example:
View attachment 268872 [/QUOTE ] "If you miss one you'll never get them all"
You are a well of know how . thanks so much . Comp. is 90 psi after i tightened the head bolts hot but it runs crappy .T. his little motor will be the death of me