70hp not running right??

poor man

Seaman
Joined
Aug 7, 2008
Messages
56
Hello yall, i have a 1970s? 70hp evinrude 3cyl, i cleaned out the carbs and washed everything out, i sync'ed(sp) them and it run prety good on the mufffs, i took it to the lake 45 miles away and it wouldnt run for crap :( it started and idle good just no power in gear, at one point i did get it run somewhat but it wouldnt plane a 15.5 foot boat :( then i went to the front of the boat and got it to plane and then it started running faster and faster and i could hear it "pick up a cyl" and go fast then drop back again. then it just boged down on its own and died, it restarted but couldnt get it over an idol.

so i dont see any adjustments on these carbs, there is the drain? on the bottom front and a hex head bolt on the top front and thats all i see. am i missing somthing? its been a LONG time since i been into a carb...

thanks for helping this dummy out :)
 

poor man

Seaman
Joined
Aug 7, 2008
Messages
56
Update

Update

ok Mod # is 70673 D

AND the top is a STRIGHT SCREW head not a hex head like i said before..

ALSO i tore the carbs bac down and cleaned and removed everything i coud and out them back to geather, narowed it down to the center carb, if i close that choke 95% of the way the engine will rev up and empty the barrel of water in about 1.2 seconds :) ask my dog LOL anyway with the choke open it will bog down and stall out......

now any ideas with this info?? thank you much...
 

poor man

Seaman
Joined
Aug 7, 2008
Messages
56
Re: 70hp not running right??

nope still no go, took it to the lake and what ran good here wouldnt even get a 15.5 ft boat out of the water :( i give up... anybody want to buy a 1976 70hp for about 400.00????? :mad:
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,765
Re: 70hp not running right??

If you have to choke the engine to make it go -- that carb has clogged high speed jets or passages. Just flushing them is not good enough. They need to be squeaky clean and blown out with compressed air. That means every nook and cranny in the carb. A needle and seat that is not functioning properly can cause this as well. Float set right??
 

David Greer

Petty Officer 1st Class
Joined
May 7, 2006
Messages
219
Re: 70hp not running right??

You have ethanol poisoning.
I have that motor (but 1988) and it is one of the best. But the crap that ethanol brings out, including water, will kill you.
Once you replace the jets get a good 20m seperator and baby your fuel.
 

Boss Hawg

Lieutenant
Joined
Apr 9, 2009
Messages
1,433
Re: 70hp not running right??

If you have to choke the engine to make it go -- that carb has clogged high speed jets or passages. Just flushing them is not good enough. They need to be squeaky clean and blown out with compressed air. That means every nook and cranny in the carb. A needle and seat that is not functioning properly can cause this as well. Float set right??

Agree- i have about the same motor (1987) & had the same problem-
I went thru the carbs GOOD along with the link 'n sync -
Did a good de-carb job on the motor & now she be runnin :D
Listen to these guys ;)
 
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