Spark, Compression, & Fuel

kmk1012 · 10-18-2009, 10:14 PM

Three weesks ago I went crabbing on my boat-it ran great! I ran all of the fuel out of it after washing it down. Long story short, now it won't run! Nothing has changed, I've tried new spark plugs, drained the float bowls, replaced the coil, I'm just stuck. It's a 1996 Johnson 48SPL with less than 135 hours on it. Any kind of direction would be greatly appriciated-maybe my best bet would be a liscenced mechanic.

Highmark · 10-19-2009, 03:05 AM

Try puting gas in the cylinder and see what it does.

Okie · 10-19-2009, 08:17 AM

It's probably some thing simple, like the gas line is not pluged in completly, It has to not be getting fuel or it would run. As you indicate it was running good before you ran it out of fuel.

Good Luck

ET · 10-20-2009, 11:44 AM

Pretty simple motor... It doesn't show ANY sign of life?

1) You've confirmed spark all the way to the spark plug, right?
2) You've confirmed fuel all the way to the cylinder, right?

Once, I've confirmed spark all the way to the spark plug, I would inject a LITTLE starting fluid into the cylinder and see if there is potential for life. If no life.... you need to double reconfirm spark.... If it pops and sputters on starting fluid, well you know it has to be fuel.

Without being there to watch you, my only guess is that fuel is not getting into the cylinders from the carb(s). Or is too much fuel flooding the cylinders? When you prime it with the bulb does the bulb get hard and the fuel stop pushing into the carbs?

It is common for the floats to get stuck in the carbs if there is no fuel in them or if the motor is tilted. Sometimes it only takes tapping the side of the carbs with a wrench to free the floats and make things right again.

BTW... I haven't run my outboard dry of fuel in over 10 years...never had a problem...

Gundog · 10-21-2009, 12:50 AM

Tap the bowl of the carb with the handle of a screw driver primer the bulb good and try to start it again.

Mike

Just-in-Time · 10-21-2009, 04:11 PM

Quote:

Originally Posted by Gundog

Tap the bowl of the carb with the handle of a screw driver primer the bulb good and try to start it again.

Mike

that will not do anything, tapping the bowl

compressed air will work better

kmk1012 · 10-22-2009, 10:10 PM

Still not running-I do however have raw fuel comming out of the exhaust from turning it over sooo much. I keep pulling the plugs, turning it over , then reinstalling the plugs and-nothing. The spark appears to be strong-in the daylight. I hope helps you guys/gals help me!

ET · 10-22-2009, 11:29 PM

Quote:

Originally Posted by kmk1012

Still not running-I do however have raw fuel comming out of the exhaust from turning it over sooo much. I keep pulling the plugs, turning it over , then reinstalling the plugs and-nothing. The spark appears to be strong-in the daylight. I hope helps you guys/gals help me!

So you do have fuel.... too much of it!!!!

I'm betting that the floats in the carbs are stuck and the cylinders are being flooded with fuel.

When you pump up the bulb, does it get hard and stop? I mean do the carbs close off so fuel just doesn't keep dumping into the cylinders?

If you can't free the floats, your only option is to open them up.

What's your experience here? Does what I'm saying make any sense to you?

MattPark · 10-23-2009, 08:18 AM

Quote:

Originally Posted by Just-in-Time

that will not do anything, tapping the bowl

compressed air will work better

Tapping the bowl can definitely pop a worn/stuck float needle loose.

Compressed air can definitely crush carburetor floats.

budnate · 10-23-2009, 09:49 AM

, unplug the fuel, drain the carb, crank it with the plugs out a bunch to air it out, dry the plugs with carb cleaner, DRY with air, then shoot a little starting fluid on each plug and small shot at the carb with the butterfly wide open, pop them back in, it should fire for a second or so, if it does, pull and go through the carbs.

starting fluid is not recomended for 2 strokes but is a quick tool when your stumped like this.

Just-in-Time · 10-27-2009, 12:49 PM

Quote:

Originally Posted by MattPark

Tapping the bowl can definitely pop a worn/stuck float needle loose.

Compressed air can definitely crush carburetor floats.

i beg to differ

how do you crush a float?
you can change the float height if you use to much pressure, but crushing the float, nope

Gundog · 10-27-2009, 01:57 PM

I can tell you I have had 2 kicker motors that had the needle valve stick and a simple rap on the bowl fixed them both one was floading and one was not getting fuel.

Mike

Bloom · 10-27-2009, 02:23 PM

I had a similar issue with an older Johnson a few years ago. After much dismantling, chin-rubbing and hair-pulling, plus a trip to the dealer, I finally discovered it was a stuck choke. Not sure about yours, but mine had a black rubber hose that led from the choke to a fitting on the side of the cylinder.

Pinching it off as I cranked it confirmed that it was the choke, since it fired right up, cleared it's throat and ran quite nice.

It's almost always something simple. Don't despair, you'll find it.

AlK · 10-28-2009, 07:08 PM

Just a thought, does the motor have a lanyard and if so make sure it is on, else your motor will never start.

MattPark · 10-28-2009, 08:09 PM

Quote:

Originally Posted by Just-in-Time

i beg to differ

how do you crush a float?
you can change the float height if you use to much pressure, but crushing the float, nope

It only takes a couple of psi to crush some metal floats. The reason they float is they are thin and filled with air. A few PSI is childs play when you are dealing with an air compressor.

I'd post a picture, but doing that will accomplish nothing here.

Just-in-Time · 10-30-2009, 01:41 PM

uhm

metal floats are not used in outboards

metal tanges, yes, which adjust float height

canned air, if the best thing on a boat, you can use it as a noise device

oh ya, carbs have vents, so if air pressure was to much air pressure would vent out!

Pilar · 10-30-2009, 02:24 PM

+1 on lanyard unplugged. Only took me a couple of days to figure it out on pretty new Yamaha T25.

kmk1012 · 10-30-2009, 09:31 PM

Tried all of the above-long story short I'm taking it in to the dealer on Monday. Probably something super simple but beyond my scope of things. Thanks for the help.

bluehewes · 11-02-2009, 11:43 AM

Quote:

Originally Posted by Pilar

+1 on lanyard unplugged. Only took me a couple of days to figure it out on pretty new Yamaha T25.

That's what I was going to suggest. or maybe it's faulty either way should be able to diagnose pretty easy.

kwik karl · 11-03-2009, 07:20 AM

Quote:

Originally Posted by bluehewes

That's what I was going to suggest. or maybe it's faulty either way should be able to diagnose pretty easy.

If the lanyard were disconnected it would have no spark to the plug.

KK

bluehewes · 11-03-2009, 05:42 PM

Quote:

Originally Posted by kwik karl

If the lanyard were disconnected it would have no spark to the plug.

KK

I thought that's what he said, OOPS.

Do you have a FWS on it? when's the last time it's been changed?

kmk1012 · 11-03-2009, 05:54 PM

New coil(again), curb adjustment, now it runs better than it ever has! I think it is kinda wierd that my last new coil only lasted about 27 hours of fun time (according to my hour meter). Is this a premature failure or just one of those things.