low idle orfices

[moored3]

I have been trying to get a 1978 70hp johnson motor to idle. I think the model is a 70E78C serial no J4071051 Every thing I read is make sure the carbs are just right . I have cleaned them twice now to no avail. Iam going to clean them and kit them one more time I am checking everything I can think of . I was checking the low idle orfices and noticed that two of them were about . 032 in dia. while the third was smaller didnt measure this one because this did not seem right. Just what is the proper diameter of the low idle orfices. I have also did a compression check 140-138-138, changed plugs gapped properly , new reeds and did a link insync. Been a mechanic for30years on large industrial engines but not on small outboards, just do it for fun Thanks I enjoy this forum

 

[iwombat]

Re: low idle orfices

Did you remove the core plug and clean out underneath?

 

[moored3]

Re: low idle orfices

Yes I did every clean

 

[guy74]

Re: low idle orfices

idle orfice part number 320016 (.032)
Hope this helps

 

[moored3]

Re: low idle orfices

thanks for the help any other ideas appreciated

 

[guy74]

Re: low idle orfices

Have you checked the spark? I had idle problems with my 1988 60hp, tried several things to fix this problem. Finally the powerpack went out, left me stranded, when I replaced the powerpack my idle issues went away. Also, make sure you don't have any airleaks that would lean it out. Does it sneeze or cough while trying to idle? Have you gone though the Link & Sync procedures for your motor? If the linkage is holding one of the carbs slightly open, it won't idle right.

 

[moored3]

Re: low idle orfices

Yes I have done a link n sync all plugs are firing . when idling though there seem to be a dominate cyl. or one cyl wrking hard the other two just goofing off ha ha I do have an extra power pack I will try that
Do you think that because the engine is so old that maby the lower seal leaking sucking air

 

[guy74]

Re: low idle orfices

I was thinking more like air leaks around the throttle shafts, or intake assembly. How fast is your idle set? Mine sure doesn't like to idle any slower than spec.

 

[moored3]

Re: low idle orfices

If it is in gear to run it has to be up arround 1000rpm or better not to stall out or I have to throttle up to keeper running