1978 75 hp

hadaveha

Petty Officer 1st Class
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Mar 17, 2009
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389
ok guys i no this is a stupid question we bought a 1978 75hp for my fathers pontoon, the problem we r having is we had to get new cables due to length, even when we had no cables it seemed to be having the same problem and that is when u start it it starts running at full rpm, its like it is wide open i can open or close the choke it really seems to make no differance. any help plzzzzzzz
 

JB

Honorary Moderator Emeritus
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Mar 25, 2001
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45,907
Re: 1978 75 hp

You need to get the OEM Service Manual and do a link 'n' synch, Dave.
 

hadaveha

Petty Officer 1st Class
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Mar 17, 2009
Messages
389
Re: 1978 75 hp

i have the manual on the way i was just baffeld at how the chole butterflys could be open, and the throtle butterflys be almost closed and the engine still revv the way it does thats by hand with cables not even attached
 

F_R

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Jul 7, 2006
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28,195
Re: 1978 75 hp

i have the manual on the way i was just baffeld at how the chole butterflys could be open, and the throtle butterflys be almost closed and the engine still revv the way it does thats by hand with cables not even attached

"Throttle butterflys almost closed" doesn't get it. They have to be completely closed-closed at idle, and the spark retarded. Idle speed is controlled by spark advance/retard. The spark is somewhat advanced before the butterflys start to cam open and the point is critical. That is "link and sync". The 3 butterflys also have to be closely synced with each other and start to open all at exactly the same time.

The chokes should all be open after it starts and has nothing to do with rpm.
 

hadaveha

Petty Officer 1st Class
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Mar 17, 2009
Messages
389
Re: 1978 75 hp

thnku u guys for the help ive orderd my manual is link and synk something even a idiot like me can do with basic hand tools
 

billy4hp

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Jan 31, 2009
Messages
245
Re: 1978 75 hp

thnku u guys for the help ive orderd my manual is link and synk something even a idiot like me can do with basic hand tools


Hope you ordered a factory manual and not a SELOC or Chilton....

Search this site for link and sync before your manual arrives, there are a few threads that have a fairly detailed explanation...

Good luck...
 
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