Fuel or timing issue?

[Txflats]

Got an 1982 evinrude 70 that died 7wks. ago no spark. Replaced the timer base with a used one same #s and fired right up. Took it out for first time today and started right up started to take off and couldnt get over 1800-2000rpm to plane out didnt die just no power. Question does timing need to be set again or does this sound like a possible fuel problem all the sudden. had no issues with power before timer base went out.

 

[Daviet]

Re: Fuel or timing issue?

I would check spark and compression, if they are OK, I would move on the the fuel system.

 

[Txflats]

Re: Fuel or timing issue?

Good Bright arc and 138-141 on all cylinders. Just couldnt see how replacing timerbase could affect timing plus it idles smooth and doesnt sound out off time. Probably just a coincidence and a fuel issue.

 

[Daviet]

Re: Fuel or timing issue?

You might check the high speed orifices and see if you have a restriction in them.

 

[Txflats]

Re: Fuel or timing issue?

I'm assuming i have to pull the carbs apart for that?

 

[Daviet]

Re: Fuel or timing issue?

Don't have to, the orifices are behind the 7/16 bowel drain screws.
It takes a special tool to remove them, made my own, but you can use a small piece of wire to check them to see if they are plugged. A bread wire tie with the plastic removed will work in a pinch.
Look at #33 below.
http://www.ishopmarine.com/ishop/js...CatFilter=BRP&eCatSupFldr=supplier-100-005-EJ

 

[tritico]

Re: Fuel or timing issue?

possibly the power pack...

 

[MRneatfreak]

Re: Fuel or timing issue?

Just as the Admiral said. By special tool, he means a shaved flat head screw driver. All you have to do is find a small flat head, and see how far you can stick in the hole, then shave with a grinder from there. The high speed jets are in there quite aways, unlike the low speed jets. Before taking them out, I would remove both of them on both sides just the outside screw (bowl drain), and blow with compressed air. That way you don't have to remove much. Then do a sea trial. If no go then try removing those jets. Beware those drain caps and jets are are bronze, thus non-magnetic. If you take the jets out make sure you check that you have the correct size installed. There will be a stamp on each one, that indicated the girth of the hole. For example on my 1" throat carbs, my high speed is a #49C and my low speed is a #25.

 

[Txflats]

Re: Fuel or timing issue?

So you're saying remove the bowl screw and the orfice is behind it?

 

[MRneatfreak]

Re: Fuel or timing issue?

Not necessarily all at once. Just remove the screw first, on both sides, and blow with air. See if that helps. If not then take out the orifice behind it and check for obstructions. Up to you.

 

[boobie]

Re: Fuel or timing issue?

What do you mean "on both sides" ?? This is a 70 hp, not a cross flow.

 

[MRneatfreak]

Re: Fuel or timing issue?

Is there only one high speed screw? I was thinking he had two orifices for the high speed and another two for the low speed PER carb?

At any rate, it wouldn't hurt to take the carb apart and blow everything out, reset the float, and double check for the correct jet numbers.

 

[boobie]

Re: Fuel or timing issue?

On a 70 hp there is only one high speed and low speed jet per carb.

 

[Txflats]

Re: Fuel or timing issue?

I'm going to remove all 3 jets and check for blockage. Just a question if one jet was to be plugged would that be enough to rob it of its higher rpm.

 

[boobie]

Re: Fuel or timing issue?

Yes !! Only running on 2 cyls.

 

[Txflats]

Re: Fuel or timing issue?

Got a chance to look at this today and blew the high speed orffices out. Started it up and ran ok but noticed when pulling plug wires off while running motor didnt change when top cylinder was killed like cyl. # 2and3. Put a spark tester in and the spark is very weak on that coil unlike the other two. Could the timer base i put in be causing a weak spark on that cylinder or is it a coil issue. Was thinking about moving it with one of the other coils to see if it kills the other cyl. but looks like they are hard wired to one plug.

 

[Daviet]

Re: Fuel or timing issue?

You can remove the wire ends out of the plug to swap them around. You will have to remove the wire ends to replace a coil anyways.

 

[Txflats]

Re: Fuel or timing issue?

You mean remove the wire end out uf the three way plug. Thanks

 

[Txflats]

Re: Fuel or timing issue?

Any thoughts on rather a bad timer base can cause weak spark on one cyl.?

 

[MRneatfreak]

Re: Fuel or timing issue?

but looks like they are hard wired to one plug.

Don't know what that means. Never worked on a 70 horse. The timer base is a lot of work/hassle. I would focus on the coil issue. Try swapping them around if you still want to troubleshoot. Or if you're ready to throw some money at it, get a new coil and see what changes.

I do have experience with spark not reaching the plug and it caused the same problem you had that it sounded like it ran better on 3 cyls than the 4 it had. Couldn't hear the problem till the o/b and boat where in the bayou. Then I could distinguish that snapping under the cowl as a spark not going to the plugs. Make sure the coil wires are routed away from eachother, not touching the head and if they have to cross make sure the wires run perpendicular not parallel to eachother.