85hp 1976 evinrude wont start?

matt85evinrude · Jan 12, 2011

hi guys! my motor has compression very good spark and wet plugs. every night after work with a bit of cranking it will start at idle and run untill i turn it off, (but if i try a manually increasing the throttle lever on the side of the carbs to increse revs it will die slowly) any way, after turning it off it wont start again for the rest of the night. any ideas guys?? im so stuck!

emdsapmgr · Jan 12, 2011

Re: 85hp 1976 evinrude wont start?

You may have two issues. Could be that after you shut it off, you have no spark. Check the spark when you crank it, with an inductive timing light. The flashes in the gun will tell you the condition of the spark at each plug. Secondly, when at idle, the carb butterflys are closed. There are special idle circuits/passages inside the carb are dedicated just to idle. These sound to be functioning properly, from your description. As soon as you advance the throttle, the carb butterflys open, and the carb starts to draw fuel from other jet passages. These may not be functioning, hence no fuel. You may have dried fuel in them, or perhaps some debris (like pcs of fuel hose, etc. inside those carb passagways.) Probably need to overhaul the carbs.

matt85evinrude · Jan 12, 2011

Re: 85hp 1976 evinrude wont start?

hi! have cleaned carbs and blew out with compressed air, no debries or blocks. so puzzled. where and how do i set up this timing light? are they the same as dar ones?

HighTrim · Jan 12, 2011

Re: 85hp 1976 evinrude wont start?

Very easy. Hook the inductive pickup to a spark plug wire, and hook the power lead on the timing light onto the battery positive lug on the starter solenoid, or simply positive battery terminal to power the light. Pull the trigger on the timing light and verify that the light is flashing. Repeat this step on each spark plug wire to verify that the wires and coils are delivering power to the plugs.

boobie · Jan 12, 2011

Re: 85hp 1976 evinrude wont start?

You said "very good spark". How did you check it ?

matt85evinrude · Jan 12, 2011

Re: 85hp 1976 evinrude wont start?

held the spark plug with insulated pliers and watched in jump a gap about half an inch easy!

emdsapmgr · Jan 13, 2011

Re: 85hp 1976 evinrude wont start?

If you are unsure on the timing light, you may be able to buy an inexpensive spark checker at any auto parts store. An outboard spark should easily jump 7/16" or more.

F_R · Jan 13, 2011

Re: 85hp 1976 evinrude wont start?

If you are telling us that it conks out if you open the throttle shafts on the carburetors, well of course it conks out. That would be the normal result. The spark has to advance in correct sync with the carburetors or it will die.

boobie · Jan 13, 2011

Re: 85hp 1976 evinrude wont start?

Are you using your control lever to advance the throttle or just moving the carb plates only ? FR is correct in what he said.

matt85evinrude · Jan 13, 2011

Re: 85hp 1976 evinrude wont start?

haha yea sorry guys! new to boats and engines! you guys are right it will just conk out! but still dies sometimes without touching anything

emdsapmgr · Jan 14, 2011

Re: 85hp 1976 evinrude wont start?

When the engine conks out, are the plugs wet or dry?

matt85evinrude · Jan 24, 2011

Re: 85hp 1976 evinrude wont start?

hey every one! success! was just the flywheel key after all! 6 dollar fix! make sure anyone reading this you torque the flywheel nut to 100 ftlbs. seriously.

85hp 1976 evinrude wont start?

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