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1974 Johnson 70Hp Power Shift 2 -Loop Charged Motor Specs

HappyOurs

New member
I have a 70ESLR74M Johnson Running a 13 1/4 x 17 Pitch Prop 29MPH @ 4350RPMS @ WOT Pushing a 1964 Evinrude Sweet 16

I realize I am not reaching Max RPM's & would like to know what Max is or if the Current setup is okay?
 
Yours at max is 5000. Is your motor's carbs' flies are level in the middle at WOT? Others would have suggested you to drop to smaller pitch? Or?
 
Thanks qhn. I have seen the Butterflies on the carbs... its almost as if they over turn slightly by maybe 15 degrees @ WOT. I have borrowed a 13 3/4 x 15 Prop to test out hopefully later tonight or tomorrow. From what I understand... 1 Degree of pitch equals a 200 RPM Change. So if thats correct I should be closer to 4800 RPM. Now All I have to do is get the timing sorted out.
 
Okay, SO had the boat out lastnight with the new 15 pitch prop. Whole shot was super quick, motor was much more responsive.... however RPM's would shoot up to 5450RPM's if allowed to be left @ WOT. Going to take the 15 Pitch back & get the guys at the local prop shop to look over my 17 (maybe repair it) Still gota set the timing though
 
I have the 73' 65HP and my WOT is 4500 to 5500 RPMs according to the manual and catalog. Check your specs.

I will be testing my new 13.75X13 soon.
 
1974 70hp
49.7 cubic inches
70hp @5000rpm
WOT rpm range 4500 - 5500
Lower unit gear 12:29
Hydro assisted shift with positive mechanical follow thru.
Those are the spec's given to me from JIMMBO on the Iboats forum.
 
Okay, SO had the boat out lastnight with the new 15 pitch prop. Whole shot was super quick, motor was much more responsive.... however RPM's would shoot up to 5450RPM's if allowed to be left @ WOT. Going to take the 15 Pitch back & get the guys at the local prop shop to look over my 17 (maybe repair it) Still gota set the timing though

You have found the perfect prop!! and on the 1st try- which rarely happens.

That motor needs to be propped to the high end of the RPM range to have any decent power at lower rpm's, since they are very low cubic inch motors.
 
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