evinrude 40hp clunking

[shawn260]

hi there, i have a 1971 evinrude ski twin 40hp. it will start and run but sounds like it has a miss fire or something clunks. i installed new plugs, points and condenser. and almost wants to stall. could it be a coil or if it was a coil u would think u wouldn't have any spark on that cylinder. and i have good spark on both cylinders tested with a quality spark tester. any help would be greatly appreciated, thanks.

 

[Cofe]

Re: evinrude 40hp clunking

Did it start clunking after you installed plugs, points, condenser?

 

[shawn260]

Re: evinrude 40hp clunking

no it was doing that before. but worse and would hardly stay running. so i checked the spark and had intermitent spark on one wire so i replaced both sets of points and condensers. and installed new spark plugs. champion j4c marine plugs. it runs better now but misses or clunks sometimes when running. could the timing be out and how would u adjust it. thanks.

 

[bktheking]

Re: evinrude 40hp clunking

Clunk or a lean sneeze, try richening up your mixture to see if it goes away.

 

[shawn260]

Re: evinrude 40hp clunking

ok ill try that. it sounds more like a miss fire or a clunking noise. but it could be a sneeze. ill try and richen the mixture. thanks.

 

[mikesea]

Re: evinrude 40hp clunking

the carb adjustment is the best place to start,did you inspect the coils while under the flywheel?they do break down over time ,just by age,usually the insulation will show signs of cracking

 

[shawn260]

Re: evinrude 40hp clunking

the guy i bought the motor from replace one coil. and the other looks fairly new as well. no cracks or burns or anything like that. good spark from both coils. ill try the carb thing and go from there. thanks for all the help. ill see what i can find out.

 

[shawn260]

Re: evinrude 40hp clunking

ok, i got it running and turned to adj. screw a little to the rich side and problem went away. but is there a way to set the carb to factory specs or an initial adj. on it or should i just leave it alone. it runs good if i raise the warm up lever a little bit to bring the idle up a bit. but when i lower the warm up lever right to the bottom it wants to stall.

 

[KB1]

Re: evinrude 40hp clunking

Sold mine last year. Great running engine.

For mine, there was a fine line at getting the "lean sneeze" out and getting too rich to try your patience w/smoking and richness at trolling. I know this is too large a motor (IMO) to idle down creeks for a couple or 5 miles, (10 horse is better) then ask it to HA when you get back in river but usually it did.

Long story longer, consider a carb redo around Santa time; for now, turn the screw on the throttle tower where your throttle cable hooks up to "up" the r's so it won't stall when hitting a gear.

ENJOY!!

 

[shawn260]

Re: evinrude 40hp clunking

ok, i had the boat out today and it seemed ok when i was going slow but when i tried to give it more and more throttle it almost wanted to stall. could it be too rich on the high speed screw? but i'll try what u said about the screw on the throttle tower. ran great when going slower. but like i said when i throtled up too much it just about died.

 

[KB1]

Re: evinrude 40hp clunking

May be too rich on high speed jet. Turn it in an RCH and try it. If it changes some, do it again, etc. Doesn't then redo carb.




be sure to keep up with your initial settings of the low/high speed needle settings as they are now compared to total screw-in (lightly) to have an initial setting when you start again to know "what up"

You'll get there, just may not be tomorrow!

 

[bktheking]

Re: evinrude 40hp clunking

Low speed I think you mean, high speed is fixed. They can be tempermental, we took the 64 40hp tonight and had to adjust it a few times, doesn't take much, there are more air holes in these carbs then the smaller motors, may be coincidental but they seem more sensitive to adjustment.

 

[shawn260]

Re: evinrude 40hp clunking

ok i'll give it a try this weekend. ill take the boat out again and play with it and see what happens. RCH (rich), is that what u mean by rch?
thanks for the replies.
shawn.