Updated After Testing - Help Needed With 115 Mercury - Runs Than Dies

[mgmidget72]

Hi All,

**click for update post**

My wife and I finally got out in our new boat for the first time yesterday (Sunday). It's a 1999 Sea Ray 180 with a Mercury 115 o/b. After going about 2/3 of a mile at idle speed down the river (whole river is a no-wake-zone) towards the Long Island Sound, the engine started running poor and then quickly died on us. Fortunately a very helpful jet-skier was near by and towed us to the nearest dock. We never did get the engine back running and latter flagged down a passing boat for a tow back to the ramp.

Some background:
- Need to "pump" throttle 3x to start engine. PO told me this (should I have ran?).
- Engine ran fine at idle and just above the previous Monday in my driveway
- Filled up with new gas the previous Monday
- Cleaned and gapped spark plugs and replaced water separator a few weeks ago

What we tried, and some observations:
- After 3 pumps of the throttle, the engine would start and idle for 3-10 seconds
- If we started at WOT (in neutral & after 3 pumps) the engine started and ran, bouncing off the rev-limiter indefinitely until I backed off the throttle. Then it died.
- Water was flowing out of the indicator hole.
- Not sure if it's coincidence, but it seemed that if my wife pumped the priming bulb after the engine started, it would run for longer at idle.

Any thoughts on where to start? If it's something basic I don't mind doing it my self, but do you think it's time to take it to a mechanic for a good once-over?

Thanks!
Scott

 

[Chris1956]

Re: Help Needed With 115 Mercury - Runs Than Dies

Re: Help Needed With 115 Mercury - Runs Than Dies

Scott, We need to figure out what motor you have. Post serial number. Is it inline 4 or inline 6 or other? Most mercs do not have accelerator pumps and pumping throttle does nothing. Did you try choking motor?

 

[mgmidget72]

Re: Help Needed With 115 Mercury - Runs Than Dies

Re: Help Needed With 115 Mercury - Runs Than Dies

Hi Chris -

S/N: OG787911
Model: 115 ELPTO
Year: 1999
Cylinders: I-4

Consistently, I have not been able to start it cold without giving it the 3 pumps, but it does start after pumping it. Until yesterday, it kept running after starting too. Even yesterday though, it would only start (and quickly die) after 3 pumps. My shop manual for the engine shows an accelerator pump diagram (pg. 3B-26).

 

[LSaulmon]

Re: Help Needed With 115 Mercury - Runs Than Dies

Re: Help Needed With 115 Mercury - Runs Than Dies

Scott, I am having simular issue with my 03 Mercury 115 - I hired a mechanic to work on my engine. He suspects the fuel pump or maybe a clogged fuel line. I have replaced the gas, added fuel additive, new spark plugs, replaced the fuel lines, and check my injectors. I recommend you have a mechanic look at your engine. You could have a carborator / injector (depending on what you motor has) issue, but in my case I did everything I could think of, yet I still have the same sympton. You should also use a fuel additive for ethinol gas, or, better yet, find a gas station that sells no ethinol gas (much or expensive fuel).

 

[aussieflash]

Re: Help Needed With 115 Mercury - Runs Than Dies

Re: Help Needed With 115 Mercury - Runs Than Dies

It does sound like fuel pump.Especially if it continues to run while pumping bulb.Can't hurt to clean carbs,filters and lines as well.

 

[mgmidget72]

Re: Help Needed With 115 Mercury - Runs Than Dies

Re: Help Needed With 115 Mercury - Runs Than Dies

Those were my two thoughts also about what the problem was - clogged inline fuel filter (the one on the engine) or fuel pump. Where I'm getting tripped up though, is that it ran steady at WOT. I would think both of these possible problems would prevent running at WOT even more than idle.

My engine is carbureted. A colleague suggested it might be a dirty idle needle. This was a general comment though, and not specific to mercs. Would this apply in my case?

Chris - you asked if I was choking the motor. Does this happen automatically, or how would I do this manually?

Thanks,
Scott

 

[mgmidget72]

Re: Help Needed With 115 Mercury - Runs Than Dies

Re: Help Needed With 115 Mercury - Runs Than Dies

Forgot to mention - I also loosened the gas cap just in case it wasn't venting.

 

[mgmidget72]

Re: Help Needed With 115 Mercury - Runs Than Dies

Re: Help Needed With 115 Mercury - Runs Than Dies

Any thoughts on the need to pump the throttle 3 times? Any connection to getting stuck on Sunday, or just a separate issue?

 

[CharlieB]

Re: Help Needed With 115 Mercury - Runs Than Dies

Re: Help Needed With 115 Mercury - Runs Than Dies

Your in-line 4 cyl is what's known as a 2 + 2 motor. It idles on only the top two cyl's until the throttle is opened then an accelerator pump gives a small squirt thru injectors to assist the bottom two cyl's to begin firing.

The 'Choke' is actually a fuel 'enrichener' solenoid that flows additional fuel to the cyl's to assist starting when the ignition key is pushed forwards (IN)

The prior owner may not have known how to choke/enrichen during starting and instead was 'pumping' the throttle.

Poor idle problems are common to aged and dirty carbs, the idle circuits are restricted and not flowing enough fuel for the top cyl's to fire correctly.

Follow this link to download acopy of the service manual

http://forums.iboats.com/showthread.php?t=309079

You will need an application like WinRAR to decompress the file and also remember the password 'ribforum'

Study the carb section, clean the carbs, adjust the linkage, timing, and accelerator pump EXACTLY as directed.

Repost your progress and any further problems or need for clarification.

 

[mgmidget72]

Re: Help Needed With 115 Mercury - Runs Than Dies

Re: Help Needed With 115 Mercury - Runs Than Dies

CharlieB - This is great! I'll take a look and let you know what I find.

Thanks

 

[mgmidget72]

Re: Help Needed With 115 Mercury - Runs Than Dies

Re: Help Needed With 115 Mercury - Runs Than Dies

Thanks for the tip about the choke! That at least made the engine fire for a few seconds before shutting off, without having to pump the throttle.

Looks like I may not have to dive into the carbs just yet. I took my water separator off and dumped it into a glass jar. It's been sitting for ~20 minutes now, and appears to be only 5% clear gas on top!! The rest is some light tan cloudy mixture. I'm guessing this means I have a bunch of water in my tank?

What's the next step? Do I pump the tank empty (how?), or run with the separator installed until it dies again & repeat?

Thanks,
Scott

 

[Wingedwheel]

Re: Help Needed With 115 Mercury - Runs Than Dies

Re: Help Needed With 115 Mercury - Runs Than Dies

You should pump your tank out. It sounds like its got bad gas. If its a built in, you can buy a cheap hand pump to get it out.

 

[mgmidget72]

Re: Help Needed With 115 Mercury - Runs Than Dies

Re: Help Needed With 115 Mercury - Runs Than Dies

Thanks wingedwheel. Yes, the tank's built in (okay, not 100%, but it's A LOT of work to get it out). Since the boat's been sitting now for a few days, the water should be at the bottom of the tank, so hopefully I won't have to pump too much out.

I got a length of fuel hose yesterday so I can try running the engine straight from a gas can. Hopefully that'll clear out any water out of the engine and also convince me that the water separator reaching capacity is my only problem.

 

[CharlieB]

Re: Help Needed With 115 Mercury - Runs Than Dies

Re: Help Needed With 115 Mercury - Runs Than Dies

Running the motor will not remove all the water laying in a carb float bowl and can damage a motor from a lack of oil as the water restricts the flow of fuel/oil mixture.

Remove the carb bowl drain plugs one at a time, drain the carb then pump the primer bulb to flush out any water drops remaining, repeat on each carb.

 

[mgmidget72]

Re: Help Needed With 115 Mercury - Runs Than Dies

Re: Help Needed With 115 Mercury - Runs Than Dies

CharlieB - oh no, not the answer I wanted to hear (but definitely appreciated)! Looks like I have some work ahead of me this afternoon.

I took a look at the carb diagram in the manual (copied below), and I don't see any bowl drain plugs. I'm guessing this means that I'm taking each bowl off?

Anyone know if it's practical to take the bowls off while the carbs are still on the engine?
Are the bowl to carb gaskets (#2) one-time use, or can I reuse them? What about the carb to engine gaskets (#14) if I have to take the carbs off?

Thanks,
Scott

 

[whodey]

Re: Help Needed With 115 Mercury - Runs Than Dies

Re: Help Needed With 115 Mercury - Runs Than Dies

#11 in ur diagram is the drain plug screw and at least on my 60hp 3 Carb merc it is impossible to remove the bowls with the Carbs still on the motor. Remove the screws and flush as previously described and you'll empty the old stuff out...

 

[mgmidget72]

Re: Help Needed With 115 Mercury - Runs Than Dies

Re: Help Needed With 115 Mercury - Runs Than Dies

So I've had some time to look into this.

Here's what I've done and noticed -
- Attached external tank, tried to run with no luck
- Drained fuel bowls (thanks whodey for pointing out the plug!)
- Now it ran GREAT on external tank
- Emptied the water separator and reinstalled
- Pumped the fuel through the separator and back into the tank, emptying the separator a few times into a clear jar
- The last two times I emptied the separator, it didn't look like there was any water in it
- Reattached the main tank to the engine, tried to run with no luck
- If I pressed the key to run the enriching pump every so often, I could keep the engine running, but it would die if I stopped
- Reattached the external tank, ran the same as with the main tank (needed to press the key)

That's where I'm at now. I haven't tried draining the bowls again to see if it would run again on the external tank. The only explanation I can see is bad gas. If the fuel pump, carbs, or the filter on the engine was bad, it wouldn't have run on the external tank. If the primary filter (the one in the tank) were clogged, tank wasn't venting, or the line was kinked, it would have ran right away on the external tank without the need to drain the bowls.

I'm just surprised that either gas could be that bad (wouldn't there be hundreds of cars stuck a few miles away from the station?) or that the engine is that susceptible to small problems with gas.

Where to go from here? I think draining the tank is an obvious next step, but I just don't have anywhere to put the gas.

Thanks,
Scott

 

[Wingedwheel]

Re: Help Needed With 115 Mercury - Runs Than Dies

Re: Help Needed With 115 Mercury - Runs Than Dies

If there was even a small amount of water in the tank, its going to get back into the carb bowl, you know, that Murphys thing.

 

[mgmidget72]

Re: Help Needed With 115 Mercury - Runs Than Dies

Re: Help Needed With 115 Mercury - Runs Than Dies

Isn't that what the water separator's supposed to do though?? From all I've heard, they're reusable, right?

 

[CharlieB]

Re: Help Needed With 115 Mercury - Runs Than Dies

Re: Help Needed With 115 Mercury - Runs Than Dies

Most water separating filters become saturated and need to be replaced.

If your boat is on a trailer and the tank is not full, you may be able to remove the fuel tank sending unit and drop a weighted hose to the bottom and suck the settled water off from under the gas.

Replace the filter, drain the float bowls again, and hopefully finally be good to go.