78 evinrude 70hp really screwed up

[mattwin7]

i just bought a 78 70hp evinrude its the first boat me or my family has ever owned so i dont know much at all about boats- the previous owner said he thought the carbs needed to be rebuilt(3inline) so i got a good deal on it without hearing it run- changed fuel line,fittings, and bulb- cranks now and idles but put it water and dies- the carb butterflies stay fully open all the time and there are missing springs and my clymer repair manual has no good pics for where the springs go someone PLEASE HELP!

 

[ezeke]

Re: 78 evinrude 70hp really screwed up

That is a good motor and it will respond to your understanding. Just go here and get the model-specific guidance that you require:

http://cgi.ebay.com/ebaymotors/1978...26453QQitemZ4603406639QQrdZ1QQsspagenameZWD1V

+o(

 

[Dhadley]

Re: 78 evinrude 70hp really screwed up

Are you looking at the throttle butterflies or the choke butterflies?

 

[mattwin7]

Re: 78 evinrude 70hp really screwed up

the ones right inside the air box when you open it?

 

[Chinewalker]

Re: 78 evinrude 70hp really screwed up

There are TWO sets of butterflys. The ones you're seeing are the chokes and they will stay open UNLESS you choke the motor at the control box or manually at the carbs.

The second set of butterflys are towards the rear of the carbs. These are your throttle plates. They should move easily and are spring-loaded to close. They are actuated by the throttle arm on the side of the engine.

What springs are missing?

Have you done a compression check? Always a good idea before moving further so you don't end up throwing good money after bad.

Also, by the sounds of it, the carbs will have to come apart to be cleaned and rebuilt.

- Scott

 

[mattwin7]

Re: 78 evinrude 70hp really screwed up

to do a compression check i have to buy a compression hook up and put where the spark plugs go right and put air into it and see how fast it leaks right?

 

[F_R]

Re: 78 evinrude 70hp really screwed up

You use a compression guage. Get the kind that screws into a spark plug hole for hands-free operation.

Then you crank the engine with the starter till the guage gets to it's highest reading.

 

[mattwin7]

Re: 78 evinrude 70hp really screwed up

what kinda compression am i looking for? sorry i never done this stuff before

 

[iwombat]

Re: 78 evinrude 70hp really screwed up

Anything 100psi+ would be real good. It's more important that they're all pretty close though. Make sure you remove ALL the plugs while cranking, otherwise you won't get proper RPMs to get a good reading in the one you're testing.

 

[mattwin7]

Re: 78 evinrude 70hp really screwed up

thanks ill buy one and let ya know what i get

 

[mattwin7]

Re: 78 evinrude 70hp really screwed up

i got about 120psi in each cylinder is that good? what should i do now?

 

[Chinewalker]

Re: 78 evinrude 70hp really screwed up

Compression sounds fairly good. It's even, which is the most important part.

I would go back into the carbs to make sure everything is clean and clear...

- Scott

 

[Silvertip]

Re: 78 evinrude 70hp really screwed up

Simply spraying carb cleaner into the carbs is a waste of time so remove them, disassemble them completely, soak them in carb cleaner and then blow them clean with compressed air. Reassemble with new kits. Make sure the floats are in good shape and replace them as well if necessary, making sure they are adjusted properly. If the carbs have idle mixture screws, before disassembly, turn them in (clockwise) until lightly seated counting the number of turns. Then when you are finished you can set them back where they were. You really need a service manual if you are inexperienced and intend to work on this engine yourself. It will reduce frustration and help making what can be very expensive mistakes.