1987 50HP evinrude.Got me guessing.

[James R]

Will not idle! Comps 125 both.
Carbs have been cleaned twice with both Carb cleaner kit and my Ultrasonic tank. Same process I have used many times. New kits.
Good strong sparks on the tester.
Replaced the VRO, which I thought defective, with a new standard pump. Getting plenty of fuel up
Have done the sync and tried various settings. There is no base Timing setting in my manual but it fires best at about 1to 2 after tdc. Will fire but will not start without bringing up the throttle and timing mechanism. Will not continue to run without holding up the throttle and timing on the lever mechanism. Runs lumpy, then relax the mechanism and she dies.
Running on my stand in the tub. Same symptoms that caused me to change the pump.
Got me stumped. Any ideas guys?

 

[bktheking]

Re: 1987 50HP evinrude.Got me guessing.

http://forums.iboats.com/showthread.php?t=387404

Reeds?

 

[jtexas]

Re: 1987 50HP evinrude.Got me guessing.

"will not start without bringing up the throttle and timing mechanism" that right there makes me think the timing is retarded. Will it not start and idle at 0? TDC?

Did you reset the TDC pointer?

 

[James R]

Re: 1987 50HP evinrude.Got me guessing.

Comps are 125 both.
Tried taking the ignition timing up to the max on the idle stop but not much different.
Will pull the flywheel to check if it has slipped. Will then do the coil measurements and stator etc.
Dont think it is reeds as it does not spit back when running. It could bear thinking about.

 

[tashasdaddy]

Re: 1987 50HP evinrude.Got me guessing.

http://forums.iboats.com/showthread.php?t=228183

set the high speed timing, the slow will take care of it's self.

did you remove jets when cleaning carbs. have you replaced fuel lines. http://forums.iboats.com/showthread.php?t=299680 do some reading here, ethanol, and carb cleaning.

 

[James R]

Re: 1987 50HP evinrude.Got me guessing.

Having set the Sync per book and adjusted the tilt of the motor so that the motor is more but not quite horizontal, there was an improvement in the idle throttle position. Still not able to close the throttles completely without dying. Holding the throttle at the point of dying tickling the choke or spraying fuel mix into the intakes brings the RPM up. Seems to indicate that shortage of fuel is the issue.
Have experienced this motor horizontal nonsense with another motor. What is your take on this?
Everything about the Ignition checks seem to be in order except for the fact that the book calls for 275 Ohms on the secondary of the ignition coils and the coils show near zero. Have compared this to other working coils and they are the same. The sparks are good on the spark tester. BS in the book.
So back to the fuel system. This is symptomatic of dirty or incorrectly set idle adjustment.
However there is no adjustment on these carbs and the carbs have now been cleaned three times. could still be a blockage I suppose.
Any suggestions would be appreciated.
Thanks.

 

[bktheking]

Re: 1987 50HP evinrude.Got me guessing.

Did you remove the top plug and lead shot when you cleaned the carbs? Did you remove the orifice as well? Maybe blocked up still and you just can't see it.

 

[James R]

Re: 1987 50HP evinrude.Got me guessing.

Thanks for that reminder.
Comp's good at 125 both.
Carbs are coming off again today and the plugs will be removed. This is the only other thing I can think of.
Bought a nice Solas prop at good price for my 1993 150 Johnson from Iboats. Free shipping guys.

 

[James R]

Re: 1987 50HP evinrude.Got me guessing.

Carbs removed and pulled the plugs and lead shot. Carbs were spotless. Did a visual thru the tube with my streamlight and ran a wire thru.Did a visual after wire and no change. Reassembled.
Air jets are thirty six per the parts list.
The timing marker is cast into the case.Checked TDC fly wheel position and all is correct.
Still got me guessing.

 

[waynehol]

Re: 1987 50HP evinrude.Got me guessing.

OK I am a bit of a novice so please take this for what it's worth

Could it be as simple as the throttle cable? There is no idle adjustment on the carb, but I know on my 90hp Johnson when the throttle lever is in idle position the carb is slightly open to an idle position. If you are holding a little throttle and it idles fine that could be the issue,

Disconnect the throttle cable, start her up and manually move the carb level till it idles correctly and then adjust the cable to to that position.

Just a thought.

 

[jtexas]

Re: 1987 50HP evinrude.Got me guessing.

wayne, your carbs should be closed at idle. The idle speed adjustment is 100% spark timing.

 

[waynehol]

Re: 1987 50HP evinrude.Got me guessing.

Thanks for the info. The more I read the more I learn!

 

[oldgradywhite]

Re: 1987 50HP evinrude.Got me guessing.

are your plugs gaped to .40? I had the same problem on my 40 I spent hundreds on other things?

 

[James R]

Re: 1987 50HP evinrude.Got me guessing.

Plugs are gapped at 30. Should they be at 40?

 

[James R]

Re: 1987 50HP evinrude.Got me guessing.

Plugs were gapped at 40.
Still the same, baby baby still the same.
Give it an extra shot of fuel with the primer and she comes up off stumbling. Runs well at higher RPM. Cannot see any issues with the crankcase or manifold. Gaskets look solid, no apparent leaks.
Hate to think bad shaft seals. If the top one is bad can usually see evidence under the flywheel.
Need more ideas please.
Thanks to you all for what you have given so far.

 

[James R]

Re: 1987 50HP evinrude.Got me guessing.

Pulled the flywheel. no evidence of a bad upper seal. Both cylinders react the same to spray fuel.
Pulled the the inlet manifold. Have ordered a new set of reeds but the existing reeds don't look bad.
Can look up the bores somewhat and they look clean. Remember I have 125 on both. The Comp tester I use frequently and it has never let me down on measurement.
Grasping at straws at this point.
Help me Rhonda, help help me Rhonda. Or someone pleeeease.

 

[bktheking]

Re: 1987 50HP evinrude.Got me guessing.

Reed normally don't "look bad", if the aren't sealing which may be hard to tell you will have idle issues, try replacing them , it's apart now.

 

[James R]

Re: 1987 50HP evinrude.Got me guessing.

Thanks for you support bktheking.
New reeds are ordered
Will let you all know how we fare.

 

[James R]

Re: 1987 50HP evinrude.Got me guessing.

Ok, new reeds and still the same. Pulled the carbs again and checked for clean. Spotless.
This motor will fire up with choke/injector sol and will run if I pump the choke but dies almost immediately if I leave it. Can see the reeds opening very slightly when turning over fast. There seems to be little suction at the manifold when blocked off. With the carbs off we get comps at 140 on each. Is it likely that the crank seals are shot. I cant think of anything else.