1970 60hp evinrude has no power under load.

[dexter88]

I have a 1970 60hp evinrude that has no power under load. I have replace all the fuel lines and connectors, new fuel pump, new plugs, and rebuilt the 3 carbs. It will sometimes die at idle but not all the time. When I run it with the miffed everything seems to work fine till I put it in the water. During idle if I pull the lower plug wire there is only a slight change in idle not much. If I pull any of the other two it dies. If any one has any suggestions please help.

 

[Bosunsmate]

Check compression(theres a sticky file at top of page on how to do that)
and spark

 

[dexter88]

I checked compression and had 120 in all cylinders. All I have done to check spark is pull the plug and turn it over. They all sparked. But iam thinking it has something to do with the spark because when I took it out it ran really well for about 15 seconds and thats it.

 

[Bosunsmate]

Pull off the ht sparkplug wires and ground them to the block then turn the engine over for a couple of seconds.
Remove the sparkplugs and check that they are all wet with fuel.
To check spark you need a sparkplug tester or a homemade one ot do it properly as although they may spark on the block they may not do it properly when in the cylinder.
You need to check they spark powerful enough to jump a 7/16 gap, a sparktester checks that

 

[ronward]

As stated above, a proper spark test is a must. If that checks out, your #1 and #3 plug wires are identical, you could try swapping those to see if problem moves to top cylinder. You said you replaced plugs but how old are the wires? Possibly you have a bad wire on #3

 

[itsaboattime]

I have a 1970 60hp evinrude that has no power under load. I have replace all the fuel lines and connectors, new fuel pump, new plugs, and rebuilt the 3 carbs. It will sometimes die at idle but not all the time. When I run it with the miffed everything seems to work fine till I put it in the water. During idle if I pull the lower plug wire there is only a slight change in idle not much. If I pull any of the other two it dies. If any one has any suggestions please help.

You rebuilt the carbs and it runs fine on muffs. Maybe your problem isn't spark. I am thinking you have a lean condition on the number three cylinder. It may run fine while lean on muffs because there is no back pressure. Once it's in the water, the back pressure from the water causes problems. If I were you, I'd recheck your carbs. A lean condition will cause no power under load.

 

[dexter88]

Ronward I do believe I have a bad wire on number 3 I was just pulling plugs while running and the number 3 was shocking me through the insulation. Is it possible to replace the wires and if so how. I talked to a marina in town and the guy told me you can't replace the wires it is one piece with the cap. I find that hard to believe.

 

[racerone]

Marina guy just does not know the older stuff !!!-------Plug wires screw into the distributor cap.-----Fairly simple stuff !

 

[dexter88]

Oh ok. I tried to get them to order some and they couldn't. Can I just make them with spark plug wire from auto zone.

 

[dexter88]

I want to get tho boat running but I am on a tight budget. I need to test my points, and cap because points are about 65 a piece and a cap if I can even find one is about 300. I only paid 600 for the boat.

 

[Bosunsmate]

run it at night, see if its arcing out where it shocked you