Bad Coils??

[Brendanpd28]

Hey All,

    Me again with MORE engine trouble.  1990 Evinrude 88 SPL.  Took boat back out of the water for carb rebuilds. Symptoms as follows: Hard to get started, fuel slick around motor (seems to be from exhaust), and VERY jumpy and sluggish at low rpm's. WOT she runs PERFECT. Mechanic thought it was low speed jets at first but after inspection said the carbs were fine.  He suggested new coils but did not sound very confident. Do these symptoms sound like coils to anyone? I would really appreciate input here....I've done quite a bit a work to this motor already. Will most likely repower or sell next year.


THANKS

[boatnamesue]

Best engine advice I can give you is the best engine advice I've received....of the 3 systems necessary for spec engine performance (fuel, spark, compression), 90% of the time the issue is fuel system related.  In my years of maintaining/repairing my own motor I've found this advice to be correct 100% of the time.  So I'd first focus on the fuel system related components, then electrical such as the coils. 

The fuel slick you're seeing around motor obviously excludes the coils as being the culprit of that in particular.  Is this the first you're seeing this slick?  Typical for older motors like yours to ooze oil/fuel, but so long as the ooze isn't a leak it's no biggie.  I'd do a full inspection of fuel system components from tank to carbs, verifying each component is within spec.  Not familiar with the carbs used in your engine, but if possible, make sure to pull each jet to clear out orifice.  Only one jet that's clogged is enough to cause poor engine performance.  Hopefully you have a service manual to guide you and provide these spec numbers.  If so, this manual will also have the spec numbers for testing the coils.

[jdupree]

What is the history with the fuel pump?  I had the same exact symptoms on a Yamaha and the fuel pump diaphragm was leaking dumping raw fuel into the exhaust.  Maybe not the problem, but I would not rule that out.

To test on most outboards, remove the bolts that attach it to the block and then pump your bulb and see if it is leaking.  If it leaks you have a ruptured diaphragm.

[Brendanpd28]

Thanks for the advice....both of you. As far as the fuel system goes: fuel tank, lines, fill, vent, separator, and pump are all new last year. Mechanic ruled out the carbs but I’m not sure I completely trust that since how could he know without disassembling them??? He was suspecting a misfire due to a bad coil. I’ve never done an outboard carb rebuild before but I may give it a whirl. Everything else I’ve done myself using my manual of course. I also had a huge issue with water getting into my tank through the vent last year before I put a clamshell over it. But I drained the carbs after that issue was fixed. Here’s a few pics of the fuel slick. Also running VERY Smokey but I think I have a little too much sea foam in the tank right now. Always appreciate the vast knowledge on this forum!

[boatnamesue]

Mechanic ruled out the carbs but I’m not sure I completely trust that since how could he know without disassembling them???

Exactly ^^^.  You might have a stuck float needle, which would cause unregulated fuel into carbs...and you can only know this by pulling carbs.  And if the mechanic suspected a bad coil, did he confirm this using a multimeter to test coil's?  No way to know it's a bad coil unless you test. 

If you enjoy the challenge of pulling things apart and putting them back together then you should take on the task of cleaning your carbs.  No better way to become comfortable with their innards and function.  Having a service manual specific to your engines model/year is key the first time around though.

[theFunsmith]

100% agree with the above statement. While carburetors may seem tricky at first, becoming familiar with their function is a skill that will pay dividends as long as you run anything a carb in the future. Techs make plenty of money on the idea that most people are too timid to jump in and try. There are a ton of youtube tutorials on carb rebuilding, and there may even be a couple out there for your exact application. Take pictures as you take things apart, and do a quick search to see if there are any downloadable manuals.

Also, it is a good idea to have a rebuild kit for your carburetor on hand. Having new gaskets there, and any parts you may need will reduce the time in between disassembly and reassembly. I find that when I am not fresh on things, I have to try twice as hard to recall how things came apart.

[Brendanpd28]

Thank you both.  Sounds like I am taking the carbs off.....I already have 2 rebuild kits.  I have searched many times in the past for videos specific to my motor but haven't had great luck.  I trust following my manual but I am very visual.  Boats in the water right now....think its ok to remove the carbs, and bring them home for the rebuild?  Possible?

Thanks!!

[boatnamesue]

Thank you both.  Sounds like I am taking the carbs off.....I already have 2 rebuild kits.  I have searched many times in the past for videos specific to my motor but haven't had great luck.  I trust following my manual but I am very visual.  Boats in the water right now....think its ok to remove the carbs, and bring them home for the rebuild?  Possible?

Thanks!!

Your service manual will be the best resource.  No issue pulling carbs while boat is submerged. 

[Brendanpd28]

Got the carbs off and pulled apart today.  All orifices, etc. looked to be clear of obstructions.  Was actually kind of hoping to find an issue so I know that was the cause of my issues lol.  Either way, cleaned everything up, blew out all of the orifices, replaced the float needles/O-rings/gaskets/etc.. Going to replace all of the coils and plug leads also just for piece of mind.  If the same issue exists after this than I am truly at a dead end.  The ONLY other thing I can think of is the primer solenoid? Or honestly just bad fuel.....started with about 5 gallons of what was left in the tank from last year (stabilized) and added 20g of fresh before first launch. This was a great learning experience either way....carb rebuilds were WAY easier than I expected. Thanks for the help all!

[boatnamesue]

Bad primer solenoid would cause difficult cold starting, but is not be associated with the fuel slick.  You can either meter test the solenoid that it's receiving 12v when activated or activate it with engine and cowling off. You should be able to hear it click.  And despite stabilizer being added to the old fuel with new fuel, IF the fuel went bad or water in the tank this would be the cause of poor performance. 

I believe the fuel/oil slick is an issue separate from poor performance. 

[theFunsmith]

If your fuel quality is in question, I would try to run off of a small portable tank full of known good fuel. It is an easy variable to eliminate.