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1999 50HP Starts but dies.

C

Calcat85

New member
Hi all, I performed a search on the threads and did not find anything that I thought would help with my issue.

Problem: Engine starts and will idle for ~10 seconds than dies. Sometimes it will restart quickly and others it takes a little bit time.

I last used the boat in May of 2019 and it started quickly and ran smooth. I use Ethilene free fuel and add stabilizer when I fill the tank. Since it had been some time since we last used the boat I charged the batteries, removed the old fuel out of the tank and filled with new Ethinal free fuel. After the battery charging was complete I placed the water flush to the motor and turned on the water. After a few times attempting to start and pumping up the fuel bulb it finally started but died within 10 seconds or so. I tried to start and then open up the throttle and it quickly dies. It did reach ~4500 RPM for abut 30 seconds once and then it started sputtering so I cut back on the throttle it quickly died.

What I have checked:
  • I have replaced all of the fuel lines and fuel filter.
  • Replaced the Crank case pulse hose to the VRO pump.
  • Tested the VRO pump by running outlet hose into a clear bottle and then cranked the engine and it pumped fuel.
    • Fuel flow was not steady (variable increase and decrease in flow) but filled the bottle fairly quickly.
    • The crank case pulse side of the VRO holds a vacuum.
  • Rebuilt both carburetors and I found them to be very clean and free of debris upon initial inspection.
  • Checked compression and both cylinders were ~140 psi.
  • Checked and cleaned spark plugs.
  • Tried pumping the fuel bulb after starting but engine still dies.


What are the next few things I should look at? It sounds like a fuel issue but could it be an electrical issue?
 
Check to see if it could be a spark problem. Remove spark plugs and look for a nice strong 7/16" crackling white/blue spark. I made a spark tester out of some alligator clips, wire, small wooden board, and 2 nails. Works great.....adjust gap with alligator clip. IMG_20200413_123938033_compress69.jpg

PS. Don't laugh, guys....works pretty good!
 
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timguy said:
Check to see if it could be a spark problem. Remove spark plugs and look for a nice strong 7/16" crackling white/blue spark. I made a spark tester out of some alligator clips, wire, small wooden board, and 2 nails. Works great.....adjust gap with alligator clip.View attachment 23109

PS. Don't laugh, guys....works pretty good!
Click to expand...

Thanks timguy, I think my neighbor has a spark tester that I can barrow.
 
I applied for a patent on this one but they said it was too ugly and didn't qualify. So instead, I intended to do a YouTube on how to construct one. Wife wouldn't record me, said I am too stupid and my spark tester is too ugly.
 
Calcat85 said:
Thanks timguy, I think my neighbor has a spark tester that I can barrow.
Click to expand...

I installed an inline spark tester this morning and it looks like it is getting a good spark. I did have to place some black tape on the backside of the clear cylinder to see the spark due to the glare but it is sparking to both spark plugs.
 
See, my tester is sooo sweet, no need for black tape either. Got 7/16 to 1/2" crackling white/blue...."lightning like" spark?
 
OK, got to thinking about the 7/16 gap and found a tester that would allow me to set that gap. Wala, once terminal off of the coil did not produce a spark and the other one did not seam as strong as it should have. I did use one spark plug wire to test both to make sure it was not a wire issue. I guess I was seeing things with the borrowed tester that lights up. Looks like I am going to have to order a new coil. Thanks for the help!

Tester.jpg
 
Let me know if you want to order my plans to build a spark tester, Cal. The other guys here will be envious. Thanks, Racer.....I keep learning from you guys. I sure miss Joe, though. I think him and me grew up in the same part of town.....only a thousand miles apart.
 
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Well, I did a little reserch on testing the coil and perfomred the Ohm Resistance test. I get 281 across one side and 320-325 across the other side. :confused: Power pack??

Coil.jpg
 
Well, I replaced the coil and the power pack and am still only getting spark out of lower half of the coil. I swapped the primary leads around but the same issue, only getting spark from the lower half of the coil. ��

Any suggestions on what to check next would be greatly appreciated!
 
Rwbutler said:
Test you timing sensor.
Click to expand...

I performed an Ohm test on the timing sensor and it checked good. Mine has the 3 pin 12A model and manual indicates it should have between 20-35 ohms and both were at 26. Tested to ground and no issues. I don't think I can check peak voltage with my meter so I have not tried that.

Thanks Rwbutler!
 
Well, still scratching my head. Went back and performed Ohm testing on the coil and the timing sensor and all is good. Still only getting spark on the bottom half of the coil. New coil, New Power pack with no change. Not sure about this test but I performed an ohm test on the 2 orange wires in the 5 pin connector coming from the stater to the power pack and it showed OL. This was in the manual for testing the charge coil. I have a peak test adapter on the way so I can test the power pack myself. Not sure if it will allow me to test the peak volts on the timing sensor or not but going to give it a go.

Any Ideas?
 
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