70hp evinrude troubles what next

boaterbrian80

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Mar 15, 2010
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I HAVE A 1975 70HP evinrude took the boat out and it idles perfect when i put it in gear it trys to go and dies well i took it home and drained the tank and changed the plugs well today with hose hooked to it, in 3/4 throttle or higher it idles up ok but after a few secs pass it misses for a sec then breaks loose and screams any ideas? for the record compression is good 120 122 121 thanks
 

JB

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Re: 70hp evinrude troubles what next

What it does with no load is lie to you. It is not making power.

May be a dead cylinder (or two).

Please try again to explain what it is doing and what you have done to try to identify the cause. Punctuation and capitalization always help. "well" is not punctuation.
 

boaterbrian80

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Re: 70hp evinrude troubles what next

best way i can explain it is when i launched it off i cranked the motor it would idle perfect as soon as I put it into gear it would bog down and die, it would start right back up no problems at I put it into gear and same issue, I ended up drifting out a ways while idling and put it into gear and it went but very hesitant I got near land and it seemed like something broke free and it started going like it should took it home and changed the plugs and changed the gas i am gonna try again over the weekend but any ideas on what i should check?
 

tx1961whaler

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May 31, 2008
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5,197
Re: 70hp evinrude troubles what next

I HAVE A 1975 70HP evinrude took the boat out and it idles perfect when i put it in gear it trys to go and dies well i took it home and drained the tank and changed the plugs well today with hose hooked to it, in 3/4 throttle or higher it idles up ok but after a few secs pass it misses for a sec then breaks loose and screams any ideas? for the record compression is good 120 122 121 thanks

Keep running it at high RPM under no load on a hose adapter and you'll blow up the motor. How the motor runs under no load is very misleading. It will run just fine on only 1 cylinder. Use a spark tester and check the spark on each cylinder first.
 

mikesea

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Oct 1, 2006
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Re: 70hp evinrude troubles what next

sounds like you have a spark leak,either a bad plug wire,or the smaller wire from powerpack to coil .be sure all connections are rust free,including the coil in the sparkplug wire to plug,be sure your coils have clean grounds,your plug wire may be grounding to block thru a crack,check all 3 ,or it could be a weak plug
 

boaterbrian80

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Mar 15, 2010
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Re: 70hp evinrude troubles what next

well it ended up being spark, my 2nd cylinder wasnt getting spark i changed the powerpack and coils and it runs like new,thanks for the advice
 
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