jet/opriface info for a 74 70hp

blueboat1

Petty Officer 3rd Class
Joined
Apr 29, 2003
Messages
81
1974 70hp johnson. it was re-jetted for high altitute. jet top #30 bottom #61d. after 7 calls to varios O/B repair shops the consisnsese is 61d High speed jet/oriface is correct for both high and low altitude. FOR HIGH ALT low speed jet/oriface #30. For SEA LEVEL needs to be a #33 or #34 depending on *use. Some books/machanics spoke of a 3rd jet/oriface in the center of bowl-it was not on this carb. just a brass tube from the bowl to the barrel/throat. Hope all the time on the phone/pc/books helps some one.<br />>}}}?> :)
 

steelespike

Supreme Mariner
Joined
Apr 26, 2002
Messages
19,069
Re: jet/opriface info for a 74 70hp

Help us out here. Its not clear what you<br />need from us.I dont have the specs on your carb but tell us what the symtoms are maybe we can tell<br />if it is jet related.
 

Hooty

Rear Admiral
Joined
Oct 2, 2001
Messages
4,496
Re: jet/opriface info for a 74 70hp

At sea level your main jet should be a 61D. 3,000-6,000ft. it should be a 58D. 6,000-10,000ft. it should be a 57D.<br /><br />c/6<br /><br />Hooty
 

blueboat1

Petty Officer 3rd Class
Joined
Apr 29, 2003
Messages
81
Re: jet/opriface info for a 74 70hp

I was just posting some info i found after a long round of phone calls and lot of board reading. Just wanting to share. After getting my new jets/oriface i will be running 61d for high and 33 for low.
 
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