1990 Evinrude 100 HP (E100STLES) Troubleshooting advice please .........

[JimInAlabama]

Hello and Happy New Year folks,

I need some advice on my 1990 Evinrude 100 HP Cross Flow from you experienced OMC guys. A little history, it had issues when I got it last spring, had carbs rebuilt and fuel pump replaced last April by marine mechanic. Been running ok until now, it hasn't been started in about a month and now it won't crank ..... it won't spit, sputter, hiccup, fart or even try to fire. Good battery with full charge, spins the motor plenty fast. Checked the plugs first and they're fine, it is getting what looks to me like healthy spark at plugs. Fuel is fresh and always treated with StarTron, and it's getting fuel through the inline filter, or at least when I pump the primer bulb there's a good flow through the filter. I pumped a quart of gas out through the supply line and it looks fine, no water. Compression was good when I bought it, shouldn't be a compression issue. So ...... fuel is not getting to the cylinders.

On an older car engine I would suspect a stuck float, but I think this engine has two, can't imagine 'em both sticking. Before I take it to the shop and spend money I really don't have, do you guys have any suggestions a shade tree guy can try??

Many thanks,
Jim

 

[emdsapmgr]

Re: 1990 Evinrude 100 HP (E100STLES) Troubleshooting advice please .........

When you are cold-start cranking the engine are the spark plugs wet or dry? That will tell you something.

 

[boobie]

Re: 1990 Evinrude 100 HP (E100STLES) Troubleshooting advice please .........

Take the air box cover off and squirt some premix fuel in the carb throats and see what happens. To check the spark you should have an open air gap tester and the spark should jump a 7/16" gap. Spark plugs don't cut it for checking spark.

 

[JimInAlabama]

Re: 1990 Evinrude 100 HP (E100STLES) Troubleshooting advice please .........

Take the air box cover off and squirt some premix fuel in the carb throats and see what happens. To check the spark you should have an open air gap tester and the spark should jump a 7/16" gap. Spark plugs don't cut it for checking spark.

Squirted a little fuel mix in the carb throats and got nothing. What I have is an "inline" spark checker, has an led type bulb and goes between plug and coil, and I am getting spark but it sounds like that may not be a reliable test. I Googled and can't find anything on an "open air gap tester", found this <http://www.fastenal.com/web/products/detail.ex?sku=0245717&ucst=t> , is this something like the type tester you're referring to?
Thanks,
Jim

 

[emdsapmgr]

Re: 1990 Evinrude 100 HP (E100STLES) Troubleshooting advice please .........

Have you got an inductive timing light? Put the lead on each plugwire while you are trying to start it. See what the flashes from the gun lamp will tell you about the spark.

 

[mekkamaz]

Re: 1990 Evinrude 100 HP (E100STLES) Troubleshooting advice please .........

When you are cold-start cranking the engine are the spark plugs wet or dry? That will tell you something.

X 2... wet or dry?

 

[boobie]

Re: 1990 Evinrude 100 HP (E100STLES) Troubleshooting advice please .........

You can buy an open air gap spark tester for around $8.00 to $10.00 at most parts houses. Napa, Advaned Auto and Auto Zone.

 

[JimInAlabama]

Re: 1990 Evinrude 100 HP (E100STLES) Troubleshooting advice please .........

Ok, the two right side (standing behind) cylinders spark 7/16" but two on left only spark 1/4". Compression between 119-121 on all 4 cyls. Plugs are dry.

 

[boobie]

Re: 1990 Evinrude 100 HP (E100STLES) Troubleshooting advice please .........

Flywheel key sheared ?? You can check this without pulling the flywheel.

 

[JimInAlabama]

Re: 1990 Evinrude 100 HP (E100STLES) Troubleshooting advice please .........

Flywheel key sheared ?? You can check this without pulling the flywheel.

Thanks again for your help and I'll check to see if timing is off, it sounds logical since it's gettin' spark and wouldn't try to crank when I fed fuel. And I did have the flywheel off in August to replace the rectifier. Torqued it to specs but used a cheap torque wrench.

These may be rookie concerns but ......
......does it concern you that the two port side cylinders will not spark as strong as the other two?
......and that the plugs are dry, doesn't appear to be getting any fuel when I try to crank it?

 

[emdsapmgr]

Re: 1990 Evinrude 100 HP (E100STLES) Troubleshooting advice please .........

The possibility of a sheared flywheel key is a good thing to check. Usually when they go, you will get some indication of firing (maybe even some backfiring thru the carbs) as you choke and crank the engine. Your first post says you get no indication of firing whatsoever. That along with your last post says the plugs are dry. That would indicate that even if the plugs were firing out of time, you would not know it if there was no fuel in the combustion chambers. Might be a good idea to check the cold-start fuel primer system. Pump up the fuel hose bulb, then pull the small fuel primer hose off the top of the upper carb. Turn the key to start and push in on the ignition key. You should see fuel pulsing out of the small fuel primer hose. If your fuel primer system is not working, that engine is really hard to start when cold. Get the engine to fire (and perhaps run) then worry about the spark difference issue.

 

[JimInAlabama]

Re: 1990 Evinrude 100 HP (E100STLES) Troubleshooting advice please .........

Got it solved ..... after a comedy of errors on my part!! Turned out to be bad gas. During a couple of rainstorms water ran in on top of the tank and seeped in through the fuel gauge sending unit.

I'll chalk it up to another lesson from the school of hard knocks ... I'm new to the Ethanol, 2 stroke thing, my last boat was before ethanol. One of the first things I did was pump out a quart of gas from the bottom of the tank. My first impression was that it looked and smelled a little "different" but I let it sit overnight and no water settled. I assumed it was the Startron additive doin' it's thing the way it should, bad assumption. The reason it didn't crank when I fed fuel directly to the carb throats was because I fed gas from the quart I pumped out of it..... duh.

So ..... I emptied the tank and had a real mechanic flush the fuel system and life is good. I resealed the sending unit and will put a diverter hose on the drain hole so water will go to the bilge instead of on the tank.

Thanks again for all your help, I now know how to troubleshoot the ignition system and with a 20+ yr old OMC I know that'll come in handy!

 

[AlTn]

Re: 1990 Evinrude 100 HP (E100STLES) Troubleshooting advice please .........

Glad you found it so quickly! No, not being smartbutt. Bad fuel can be a tailchaser.