1976 70hp. Evenrude

[crankykjun]

Not sure what the problem is but the motor idles great but when you give it the throttle to get the boat on plane it just seems not to have any power....it will do that almost everytime then all of a sudden like there is another motor on the back it will plane off with no problem and run great...till i need to take off again...I've changed all coils, plugs, rebuilt carbs, and still the same problem i also checked engine compression but I'm not sure what it's supposed to be at, they all tested at 145

 

[scarchest]

Re: 1976 70hp. Evenrude

Could possibly be the wrong prop for the boat that you have. Do you have a tachometer?<br />What RPM at WOT

 

[crankykjun]

Re: 1976 70hp. Evenrude

the prop i'm using is a 13 1/4 by 17 once it's up and running it turns 5500 rpm,s

 

[JB]

Re: 1976 70hp. Evenrude

Hi, Crankyjun. I think you are losing a cylinder, probably a loose connection interfering with ignition. Your engine will idle smoothly on 2 cylinders. <br /><br />Try pulling each plug wire and see what happens. If there is no change you have a dead cylinder. Inspect the plugs. A dry plug has been firing or not getting fuel, a wet plug has gas but no spark. <br /><br />Good luck.<br />Red sky at night. . .<br />JB

 

[scarchest]

Re: 1976 70hp. Evenrude

Cranky<br /><br />Done a little thinking, seems to me that there was a factory bulliten on that. If I remember correctly, the carbs need a reconstruction, will have to do some digging<br />but I think that I can find it<br /><br />Scar

 

[crankykjun]

Re: 1976 70hp. Evenrude

thanks any help would be appreciated

 

[scarchest]

Re: 1976 70hp. Evenrude

cranky<br />found service bulletin. It is Johnson SB-#1429. If you do not have access send email<br />address and I will send it to you<br /><br />Scar

 

[crankykjun]

Re: 1976 70hp. Evenrude

Email Address Is: crankykjun@aol.com