Not getting gas to the cylinders

[Sandra]

He's getting fuel from the fuel pump and it's pumping. When the ball to the tank is tight he can see that he's getting gas to the the accelorator pump because the two hoses have gas dripping from them. But he's not getting gas to the cylinders for some reason because the spark plugs are not wet and don't even smell like gas. I want to thank everyone for their help so far.

 

[JB]

Re: Not getting gas to the cylinders

What engine did you say that is, Sandra??

 

[Sandra]

Re: Not getting gas to the cylinders

a 1995 Mariner 115 hp outboard Serial Number 0G226705

 

[CharlieB]

Re: Not getting gas to the cylinders

Your 115 4 Cyl is the 2 + 2 design.

This engine (same one as on my boat) only idles on the top two cyl's. The carbs on the bottom two cyl's do not have idle circuits and pass no fuel until the throttle is opened. This is why there is an accelerator pump plumbed into only those bottom two cyl's, to give that small squirt of fuel to start them firing as the throttle is opening, once the throttle is open then fuel is drawn thru the main jet same as the top carbs.

There should not be any fuel leaking from anywhere.

Any leaking hose or fitting must be dealt with immediately.

Now that he knows that the bottom two plugs are supposed to be dry at an idle, can you be a little more specific about the problem(s) he has with the motor? Cranks but won't start, won't idle, dies, etc.

Just remember that you are our eyes and ears, good descriptions of the symptoms and what he has already checked will help us greatly to direct him to solving this problem.

 

[Sandra]

Re: Not getting gas to the cylinders

Here's from the start, we got the boat from my brother, it's probably only been in the water maybe 6 times, it propbably only has about 40 hours on it.
Bill, my husband, pulled the cover off and it shines like new in there. My brother tore all the wiring out and was re-working the wiring. After he thought he had it hooked up the right way it wouldn't start so he gave up now we have the boat. The wiring in the boat, not the engines wiring. New switch, gauges and throttle control. The wiring diagram he used was not correct, Bill went by the Seloc Outboards 1990-00 Repair Manual and re-wired it. Now all seems to be working, he has fire, engine spins, he can hear the enricher clicking when he pushes the choke button. The fuel pump is pumping gas to the top. He can choke it all day and he's not getting a sputter or a glimps of life from it. It's like it's not getting fuel to the cylinders. He knows those two lines were leaking, but he put a good amount of pressure on the bulb before they started to leak. He found one hose that was bad and replaced it and it didn't matter. He intends to replace them all, but at this point he doesn't see anything else leaking. He thinks he should at least be getting a sputter of life from it. The top two plugs look just like they did when he took them out of the box and put them in. It seems like no gas is making it from the carburators. He's had people tell him that one little thing can screw up the whole works so messing with it is a little intimidating. He can rip a car, truck, mower apart with no problem. Can it be that the enricher id bad, that it clicks, but just doesn't work because the boat sat all that time?

 

[sschefer]

Re: Not getting gas to the cylinders

Sandra, it does sound like an enrichner problem. There are two fuel lines on the enrichner. Get something to catch the fuel then take them both off. One of them should flow fuel and the other should not, (maybe a few drops).
If there is no fuel let us know and we'll take you to the next step. Whatever you do, don't blow air into the lines trying to clear them. If there is gunk in there it will end up in your carbs.

Steve

 

[CharlieB]

Re: Not getting gas to the cylinders

Brother-in-Law may have killed the ignition system in his attempt to re-wire the boat.

I suspect that your he had it wired to put 12 volts to this ignition wire which would have fried the ignition module. However, do NOT oder a new module just yet, there is NO RETURN on electrical parts so you should test the stator and triggers to be sure that you do not have some other problem.

The ignition system is a 'Ground-to-Kill' using the black wire with a Yellow trace line on it to ground and Kill the ignition when either the key is turned OFF or the lanyard is pulled.

Check for adequate spark on all cyl's. There is a big difference between having a small spark and having adequate spark. Use an adjustable spark gap tester set to 7/16 inch, or build your own. Joe Reeve's posted here somewhere instructions for an easy to build tester using a 2 X 4, 5 nails, and some wire.

Make sure that you have a 7/16 inch gap with a HOT bright blue 'crack' on each plug wire. There is a minimum cranking speed of 300 RPM so make sure the battery is charged, all cables clean and tight.

If you fail to get adequate spark then disconnect the kill wire (black w/yellow trace) from the connector at the ignition module and retest.

 

[Sandra]

Re: Not getting gas to the cylinders

He's getting fuel to the enricher when he turns the motor over. When he turns the key on and pushes on the choke gas pumps out of the enricher. He took the oil resevoir off the side and he took the tubing off where it goes to the enricher and the two cylinders. He held them straight out and up to the sun and he could see through the hoses and the tee, it was clean inside. He put the hoses back on and he took the screws out and drained the gas that was in the carborator bowls out and let all the gas that was in each one of them out. He turned it over to refill the bowls and gas came out of the face of two of the carborators and now when you hit the choke the enricher leaks and it didn't leak before and he still doesn't seem to be getting gas to the cylinders. He said that with anything else when you pump that much gas to something and choke it gas would be getting to the cylinders and the plugs would be wet. Could it be that from setting all that time with fuel in the bowls that the floats and needles could be stuck? Thanks for all your help.

 

[CharlieB]

Re: Not getting gas to the cylinders

Have him test the fuel pump output by disconnecting the fuel line between the fuel pump and carbs, crank the motor over and observe the fuel flow, it should be a strong pulsed flow.

The enrichener relys on fuel pressure from the pulse pump while cranking to pump fuel thru the enrichener valve to the cyl's.

The lower cyl's do not have idle jets and will NOT pass fuel at an idle, the lower two spark plugs will remain DRY.

He MUST TEST for adequate spark on ALL cyl's, without, it will never fire and run well.

If he drained the float bowls one at a time, and pumped the primer bulb or cranked the motor with each drain plug out he would see fuel delivered to the carbs.

If the small plug just to the left of the idle mixture screw has been removed from the carbs then there would be a serious vacuum leak within the carb and NO fuel would be passed by that carb, however, if the fuel pump is working and the enrichener is energized by pressing IN on the ignition key while cranking then the top two spark plugs should be wetted, but still, if the ignition was killed by a previous wiring problem, the motor would not have spark and will not fire.

 

[Sandra]

Re: Not getting gas to the cylinders

We just came back in the house, we tried and made a spark tester like Joe Reeves said and there was no spark. He stuck the wire in the in the spark plug wire boot and held it to what he knows is a good ground and he had the smallest little blue spark from all four. He knows it's damp outside and if he was getting a good charge it would have jolted him by holding the wire the way he was. Now when he pulls a spark plug out and turns the motor over the starter jumps out. When it has all the plugs in it, it doesn't jump out, it didn't do that before.

 

[sschefer]

Re: Not getting gas to the cylinders

The starter jumping out is an indication of some fire on at least one cylinder. That's a good thing. Keep cleaning up connections now and you might just get it. Best of luck.

 

[Sandra]

Re: Not getting gas to the cylinders

I do not see that,because we had all the plug wires off. And a plug out when it did it. with the plugs in it did not jump out. He thinks the solenoid is kicking out.

 

[CharlieB]

Re: Not getting gas to the cylinders

A small spark outside the motor is not enough voltage to fire the plug once under compression inside the cyl.

He needs to test the stator and triggers following the directions clearly spelled out in the FREE Ignition Troubleshooting Guide available for download at CDIElectronics.com

Did he disconnect the Black wire w/Yellow trace line from the ignition module and retest for spark? If adequate spark then occurs there is a problem with the wiring, grounding this wire somewhere and killing spark.

 

[Sandra]

Re: Not getting gas to the cylinders

Well, now with a tiny spark he has a problem. Is it the stater,trigger,coil packs or all the above. my husband said from the start my butt head brother may have fried something by wireing it wrong. He had power comeing from the fuse box to the starter switch and wires in the wrong places. Oh what a ordeal its been. My husband has been after this boat for years sinces my brother started letting it sit, now I think he wishs other wise. We thank you guys for letting us pick your brains, and if you have any thoughts of what he should check now it would be a great help. He has put a lot of time and money in replaceing all new things in the boat and more. And now he seems about fed up with it and thats not like him. Thanks again for all the help.

 

[Sandra]

Re: Not getting gas to the cylinders

thanks, he will check that now. Sorry I did not see your post before I sent the last one

 

[Sandra]

Re: Not getting gas to the cylinders

Hello, We pulled the black with yellow like you said and it still acts the same. it is hard to see the little spark in the day light, but he thinks he should have heard a crack from it if it was a good spark or seen something.

 

[sschefer]

Re: Not getting gas to the cylinders

O.K. so now that you've done all the hocus pocus trouble shooting you can, it's time to get systematic using a trouble shooting guide. If you don't already have one, get the Merc Manual for this motor. There's a sticky here at the top of the forum with a link to manuals. You can also find them on CD's on eBay Motors under Mercury Outboards. These are inexpensive and often the seller will email you the parts of the manual you need right away.

If you want the full factory service manual in hard cover you can buy them from Mercury. They run about $100.00 each.

In the manual is a set of very concise trouble shooting guides that will take you step by step to the solution.

We're to the point now where not being there is making it extremely difficult to proceed without sending you on a bunch of wild goose chases.

Some of the basic tools that you'll need will be a compression gauge, multi-meter and DVA adapter for the multi-meter. The cost of these tools is often less than the price of replacing a part like a stator that isn't bad.

Hope this helps.

Steve

 

[CharlieB]

Re: Not getting gas to the cylinders

Go here to download a copy of the service manual

http://forums.iboats.com/showpost.php?p=2072211&postcount=3

Remember that you will need the password "ribforum" to unpack the compressed file.

Pay attention to the wiring diagrams, your motor is a 'Ground-to-Kill' ignition, if BIL installed a generic auto ignition switch which wired 12V to this ignition it damaged the ignition module causing your weak spark condition. Before you replace the module you must be SURE that the ignition switch is correct and wired correctly or you risk damaging a new module again.

That's assuming that you fix the ignition system before you fix the wiring problem.

That Black wire w/yellow trace line that you unplugged from the wiring harness, tested with an Ohm's meter should go to ground with the key turned OFF or the lanyard if pulled off. NEVER should you see any voltage there with the key On.

The most likely problem is a fried ignition module, BUT, as there is NO RETURN on electrical parts you should make double sure that the stator is generating sufficient voltage when cranking AND that cranking speed is at least at the 300 RPM minimum required before even thinking of spending any money on a new module.

 

[Sandra]

Re: Not getting gas to the cylinders

Hello, We down loaded the manual. Bill has the key switch wired the way it shows in the book on page 2a-35. when we got the boat it was wired to the fuse box for power,Bill said then it my have fried something.
is a dva a volt meter ?Thanks again Over the weekend or maybe before he will start checking and testing. Knowing Bill he will start tonight.LOL

 

[sschefer]

Re: Not getting gas to the cylinders

Hello, We down loaded the manual. Bill has the key switch wired the way it shows in the book on page 2a-35. when we got the boat it was wired to the fuse box for power,Bill said then it my have fried something.
is a dva a volt meter ?Thanks again Over the weekend or maybe before he will start checking and testing. Knowing Bill he will start tonight.LOL

Multi Meters can't react quick enough to read what is known as peak voltage. They show you an average over time instead and it's always less than peak. When you check your stator you will use a multi-meter / volt meter with a DVA attached. Without going into all the tech mumbo jumbo, the DVA will allow you to read the voltages that the are referenced in the Service Manual without doing a boat load of math.