Issues On Foggy Days...

[WhiteRice]

97 Evinrude 25HP # Cyl with Rope Start

This has happened on more than one foggy day (3 that I can count) and very damp / cold nights. Motor starts up fine at the beginning of the day. I then make a few 15 - 20 minutes runs at WOT to different fishing spots, shut down the motor and fish for a bit. Go to start the motor again and it just will not turn over. I have discovered through trial and error that the only way I can get it going again is to pull all three spark plugs, pull start the motor 8-10 times with the plugs out to clear the cylinders, then it will fire right up and run like a champ until I turn it off again. Then I have to repeat this process. This only happens on very foggy mornings or very damp / cold nights. This motor has a single silencer that covers all three carb throats and when I tilt the motor forward, the fuel that dribbles out of the carb throats does not appear to be moisture mixed (not milky).

This motor does NOT do this on normal days with average humidity. Looking for some causes and possible solutions that do not involve staying in when it's foggy or damp...lol

 

[gm280]

When you say it won't turn over, do you mean it is locked up and not turning? And when you take out the plugs are then covered in fuel or water?

 

[Joe Reeves]

WhiteRice.... As gm280 states in not so many words, that terminology of "It just won't turn over" pertains to the rotation of the crankshaft/flywheel. Do you actually mean that the engine's electric starter won't turn the engine over... OR... are you saying that the engine turns/cranks over normally but won't fire/start/run?

 

[racerone]

Doubt that it even has electric start.

 

[WhiteRice]

Please excuse the terminology... It IS a rope start. The crank will turn but the motor will not fire. When the plugs come out, they are oily and do not appear to have any moisture on them. Running a 50:1 mix and fuel was less than 2 weeks old.

 

[kbait]

It’s obviously flooding on restart.. some things to try on restart:
-no choke
-advance throttle fully in neutral to get more air with fuel

Also, have throttle set as low as possible when you shut it down to minimize unburned fuel drawn into cylinders.. hopefully resulting in easy restart.

Re-adjust low speed mixture needle(s). If too rich, flooding may occur.

Good luck!

 

[WhiteRice]

Thanks kbait. All of the procedures you mentioned are in full practice. I haven't had any issues with restart on days other than foggy or very damp / cold ones.

 

[Bosunsmate]

Have you tried wiping down the head with a towel before restarting? Perhaps there is excessive condensation in there as the engine area cools resulting in more water droplets (that whole dew point thing) and shorting of the sparkplugs somehow

 

[Joe Reeves]

Doubt that it even has electric start.

Aha!.... And there you have it!

 

[WhiteRice]

Bosunsmate, I was thinking about something along those lines. I'm wondering if there is excessive condensation building up in the carb throats while the motor is cooling from a run. Is there a solution to this? Possibly re-prime the bulb to ensure the bowls are completely full prior to restart? Are the ported holes in the silencer allowing for too much moisture on saturated days? Is there something similar to an "oil saturated air filter" (similar to a K&N) that could help trap moisture prior to entering the carbs? Or is this just the nature of the beast and condensation is just going to get the best of this motor? I hope not :-/

 

[gm280]

Wow, hard to believe that much moisture is shorting out the plugs. Your fuel levels in the carbs bowls are set correctly aren't they? If they are too high, they could be flooding into the engine and that could be the issue. During warm/hot days, the fuel could vaporize off and it cranks correctly. But colder days it doesn't flash off as easily and floods during restart. IDK, just thinking out loud...

 

[oldboat1]

What model number is that? Sounds like ignition system, offhand. Checked wire insulation for cracking? Kill switch for shorting?

 

[Bosunsmate]

If you have a induced timing light, test for spark next time it doesnt crank. If you use a spark tester id reckon that putting that in place would just interfere with what may of caused the problem (ie a condensation trail).
Id be surprised if the fuel did absorb water that quickly but you could try as an experiment emptying the fuel carbs via the drain plugs when you stop (making sure not to prime them up) and only repriming when about to use so the fresh fuel in the carbs hasnt had time for any atmosphere contamination.
I have seen boats hard to start after having a bit of water get in through leaky fuel guage or airvents but that was after a lot of rain, never from fresh fuel being contaminated by moist air.
So will be interested to hear what you can find out so keep posting

 

[WhiteRice]

gm280 - I believe they are. I haven't had any issues and they carbs were rebuilt (including float bowl needles) 4 months ago. I will check them for sticking but I know the floats were set level with the bowl base using the line on the float as a reference.

oldboat1 - This is a E25RMEUR. The plug wires are new as of Sept 2018. Replaced them when I saw one had a split in the insulation. I will double check them for cracks. I did pull my brwn / ylw wire from the harness (kill wire) and it still didn't start until I went through my annoying procedure.

Bosunsmate - The first time I ran into this, I did check for spark from all three wires and each had a visible spark while pulling the rope with the plug out of the cylinder.

 

[Bosunsmate]

Yep but when you pulled the plug out of the cylinder to check that that also would break any condensation trail that was causing the short, thats why i thought only a timing light could confirm that, not a spark tester.
If your area is like mine here in New Zealand fog is quite a seasonal thing, mostly late autumn early winter

 

[thatone123]

I have had this type of problem in various snowmobiles. Run perfect but hard to warm up at first start or restart when hot. One hack some may like that I recently found out from my son is to carry one of those long lighters used for fires and fireplaces and etc. I was amazed when he stuck that down the cylinder of a flooded snowmobile pressed the trigger and wa-la, the flooded gas burned off and it started pronto. Did not seem dangerous in any way!

 

[thatone123]

I mean it started after the excess fuel was burned off, not during the lighter burn off process. No reason this would not work on outboards also.

 

[racerone]

Is the thermostat working properly , yes or no ?

 

[tomhath]

Yep but when you pulled the plug out of the cylinder to check that that also would break any condensation trail that was causing the short...

If you still suspect condensation, one thing to try is spraying a little WD40 on the wires before trying to start it. The "WD" stands for Water Displacement and it really does help reduce arcing caused by moisture.

However...my guess is that you are getting condensation in the carb throat or intake manifold because they will be very cold from the carb's venturi effect and evaporation of fuel, then the first few pulls of the starter rope sucks that water into the cylinder. Maybe drying the plugs when it happens is the best option.

 

[racerone]

Some simple trouble shooting will likely correct the issue with this motor !