70HP Evinrude Wont take off bad powerpack?

[miichael18]

ok guys heres the story. 70HP evinrude took it out fired right up ran it about a mile up lake and it started cutting out loss of power. it would try to go then lose all power and would only run like 10mph wide open. it idles perfect but when you put it in gear it just bogs and dies everytime. has no power. So im thinking maybe carbs was dirty. took all 3 off cleaned good, checked firing all 3 coild firing good and put fresh plugs. checked compression all around 100 psi no big diffrences. Took it to lake same thing. fires right up idle perfect but when i put it in gear it just dies and when i do get it to go it will not open up and only runs very slow like its only running on 1 cylinder. I have changed the power pack 4 years ago the old one just died and engine would not fire at all. im getting good fire clean carbs idles fine but will not go when put in it just chugs and bogs and dies most time with no power. is this another bad power pack?? i hate to throw $120 bucks for a new one without getting more info or other things to check first. any info would be great thanks.

 

[Joe Reeves]

Re: 70HP Evinrude Wont take off bad powerpack?

Check the stator under the flywheel to see if there's any sticky looking substance dripping down from it on the timer base and powerhead. If so, that would result in a voltage drop to the powerpack, needed to energize the ignition.

Remove the Black/Yellow wire from the powerpack, then connect a volt meter between that wire and ground. Turn the key to the ON position (engine not running). If any voltage registers, the usual cause is a shorted ignition switch, in which case, replace the switch. Any voltage, even a microvolt will destroy the powerpack in a short time.

It's important that you check the spark with the spark plugs removed, and that you check to see that the spark will jump a 7/16" gap with a strong blue lightning like flame... a real SNAP! Checking spark with the plugs is a waste of time.... the 7/16" gap is required.

While checking the spark, move the throttle so that the timer base under the flywheel moves from the idle position to it full spark advance position. If the spark remains the same, all is well in the ignition department.

The brass high speed jets are located in the bottom center portion of the float chambers. Did you manually clean them out with a piece of single strand steel wire? If not, do so as solvent really doesn't do the cleaning job in that area. A fouled high speed jet would cause your explained problem. It's unlikely they're fouled as you state that the engine ran a mile up the lake before it started to cut out BUT debris within the fuel system could work its way back into them.

If the spark and compression checks out (7/16" gap and 100+ psi), that leaves the fuel system. Actually the compression on that model should be higher than the 100 psi you mentioned.

What year is that 70hp, model number?

 

[miichael18]

Re: 70HP Evinrude Wont take off bad powerpack?

its a 1974. i put new stator and power pack on it about 4 years ago. it idles perfect just wont take off. i can get it to take off but it will not open up just runs very slow with no power. i was told 4 years ago the stator was bad because it was leaking and after i paid 300 bucks for a new one it didnt fix my problem then it ended up being the power pack. i still got the old stator.

 

[Stokes81]

I'm interested in seeing where this goes. I think Imy having the same issue. I've got the same problem with my late 70s 70hp evinrude. I was wondering, when your throttling up to the point of full throttle . Is the motor stumbling a bit somewhere in the middle ? I've noticed on mine when it's running good the motor runs smooth all the way through the range of throttle from low speed to wide open. But when it's giving me the issue your talking about I can feel it struggling at half way open but when I push it to wide open it goes smooth again just no high rpm. Just curious as this may be something which may lead to a solution.

 

[GA_Boater]

I'm interested in seeing where this goes. I think Imy having the same issue. I've got the same problem with my late 70s 70hp evinrude. I was wondering, when your throttling up to the point of full throttle . Is the motor stumbling a bit somewhere in the middle ? I've noticed on mine when it's running good the motor runs smooth all the way through the range of throttle from low speed to wide open. But when it's giving me the issue your talking about I can feel it struggling at half way open but when I push it to wide open it goes smooth again just no high rpm. Just curious as this may be something which may lead to a solution.

It went. FIVE years ago.

Stokes81 Read the Help Tip on top of the page about posting in old, inactive threads. You have a thread going.

Closed.