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Mercury 125 ELPTO Hot Start Problems

R

radjxf

New member
Hey guys, I have a very frustrating situation that myself and the local boat repair shop haven't quite been able to solve. I'll try to organize this so as not to leave a wall of text:

The problem:
Boat won't start after it's good and warmed up, then shut off for a while. Seems to start OK if only shut off very briefly. However, if you shut it off and say fish on an island for 30 minutes to an hour plus, this is when it won't start. Just cranks and cranks and cranks. Doesn't seem to "fire" a bit. You can spray ether or carb cleaner directly into the carbs--still no luck. Let it cool off for 4+ hours or better yet until the next day, and it starts right up!! Maddening!

Engine:
2000 Mercury 125hp ELPTO 2+2, 2-stroke with oil injection.
Motor has good, even compression (I think around 118 per cyl).
Plugs are relatively new. New inline fuel filter.
Recent water pump kit installed in lower unit.
Runs good at WOT, a little "slobbery" at idle (maybe this is normal for an old 2-stroke).
Fresh out of the boat repair shop. They installed a supplemental electric fuel pump in an attempt to help if it was a vapor lock issue. It's wired to the key so it pumps when you turn the key on. $650 later---still doesn't start when hot!!! They also supposedly cleaned all the carbs, inspected the jets, set the timing and adjusted the air/fuel mix. Very first trip out after all of this expensive work and she left us stranded! Thankfully we had our trolling motor to get us back to the marina after 1.5 hrs of trolling against the Montana wind!

Unfortunately, I did not have the right size plug wrench to pull a plug and check for spark when it was not starting. I only had a multi-tool, so all I could do was pull off the incoming fuel line to the filter (the only one that has a screw-clamp, the others are like 'zip-ties'). Strong amount of fuel being pumped in, so the electric pump seemed to be working fine. I tried spraying highly-flammable carb cleaner directly into the carbs while cranking---just kept on cranking--wouldn't fire a bit!! Seemed to be getting lots of fuel, so maybe some strange transient ignition problem only when hot??

Thanks in advance for any light you guys could shed on this situation. I have no confidence taking this boat out anymore, as we use it in Montana lakes where there is NO cell phone coverage, very few people around, and given the weather and terrain the unreliability of this boat puts us in a dangerous situation. Very few places around here that even work on boats, and most have pretty poor reputations and charge BIG $$$. I am at the point where I can't afford to put much more money into this thing before I throw in the towel. Thanks again!
 
Step # 1 for you is to test the starter.-------Costs no money !--------Take it apart.-----Then do an ohm check from shaft to commutator.---------Maybe clean and install new brushes too.-----------Slow cranking means no spark and no start !
 
racerone said:
Step # 1 for you is to test the starter.-------Costs no money !--------Take it apart.-----Then do an ohm check from shaft to commutator.---------Maybe clean and install new brushes too.-----------Slow cranking means no spark and no start !
Click to expand...

Thanks for the advice. However, when it doesn't start, the starter runs very fast. Not slow cranking in the least...
 
If you can do some testing under live conditions you can narrow it down.

You say it starts fine cold and then after running for a bit and then sitting shut off, it won't restart.

If you can get back "close to the dock" after running for a bit then shut it down and let her sit, upon trying to restart and getting a "no go", you can check for spark with a timing light - don't have to get fancy, even one of those cheapy timing lights that simply clip over the spark plug wire.

If you have "no spark", then as suggested in the above post you may have a stator issue.

Sometimes the stator windings will develop cracks (with age), when it's cold and the copper is "shrunk" you have continuity - but once warmed up the copper expands, loses connectivity and you get "no spark".

That would be my first order of troubleshooting - confirm a spark/no-spark when it won't start - that will allow you to rule out, or cause further investigation of the ignition system.
 
After lurking here even more, and also of course the above recommendations things sure point to a stator that cannot put out the "juice" when it gets hot. If a guy were to remove the flywheel to replace the stator, how do you keep the timing from moving out of spec? I'll assume given the flywheel is keyed in place, you can't mess it up by simply removing and replacing the flywheel?
 
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The timing is controlled by the trigger/trigger plate on non-computerized ignitions and is not effected by removing the flywheel and stator provided that you leave the trigger alone and any linkages connected to it (if applicable).

The flywheel, which is oriented by the key prevents you from mounting it incorrectly so a simple stator swap and replacement of the flywheel will not affect the timing.
 
Thanks again for all the helpful replies. In my limited research I see that each time a stator is replaced, it is recommended that the "switch box" also be replaced. Unless I'm mistaken, this engine does not appear to have a switch box? I see the stator, voltage regulator, 4 coils and a trigger....
 
I believe you have the CDI ignition so each cylinder has it's own "little switchbox" integral to the coils.

And I typically wouldn't replace the switch box just because the stator was changed unless there was some indication to do so. It certainly wouldn't be a "routine replacement" for me.
 
So, I picked up a new CDI brand stator and installed it this weekend along with new NGK plugs gapped to 0.040". The old plugs looked OK, a little oily however. Old stator was the "red" one with the plastic encasing the windings. Looked OK to me, no signs of melting or any contact from the flywheel.

After this, she very reluctantly starts after being run, warmed up and shut off. And I mean it took cranking and cranking and priming and fast idle lever, etc. to get it to catch and run. Probably took at least 5 minutes of trying to get it to start.

Once running, it slobbers around idling poorly and keeps dying. The only thing that keeps it going is to constantly push in on the key primer. Remember, this is AFTER the local shop installed an electric fuel pump, cleaned out the carbs, adjusted the air/fuel mixture and set the timing!

I'm out of ideas and will admit I just don't have the know-how or equipment to properly diagnose this thing. Going back ONE LAST time to the shop. If they can't fix it (not much confidence they know what to do) it's GONE.
 
yzf125 said:
So was it doing all these same symptoms before installing the new stator ?
Click to expand...

Short answer is yes. Was getting progressively harder to start after being shut off, then left off for a while. That's the key: must be shut off then left off for 30+ minutes. If you turn it off warm, and immediately try to start it, it will after some effort start up. But when you let it rest for a while like when electric trolling, that's when it refuses to start. I wonder if having the motor trimmed up contributes to this in some way??

That's what led me to spend an arm and a leg at the boat shop for the repairs mentioned in the original post. After that I took it out and started better cold, but when hot flat would not start period. Had to trailer it back home and cancelled the rest of that trip.

Now, after I replaced the stator this weekend, it will very, very reluctantly start when warm, but doesn't want to stay running. Not sure if out of dumb luck I really made an improvement or not...

Bottom line, cold starting is improved, but hot starting after letting sit is terrible or just not going to happen...
 
Update: Took it to the boat shop on May 3, got it back on June 23:eek: They took out the fuel pump pressure regulator, "adjusted carbs and timing" and claimed it was all just bad gas! They pumped out all the gas and I replaced it with 87 octane fuel plus Star Tron additive.

They said they ran it [on the lake] with an external, remote tank and again claim it ran OK. After almost two months and another bill I take it out and it will now ONLY start with the fast idle lever all the way up---no other way. Idles mostly OK in neutral, but dies when you put it in gear. Lots of fun trying to back out of or into the slip in Montana wind when the boat dies 12 times! The hotter and more you run it, the worse this condition gets.

I tried adjusting up the idle higher while it was in forward gear tied to the dock. Also repeated this out in the middle of the lake. Now it simply idles a little too fast in neutral, clunks louder when you put it in gear, then still keeps dying. Runs good as always when all 4 carbs are kicked in above 2000 rpm, but anything below and it just falls apart.
At my wits end here. Any ideas before I offload this thing for a huge loss?? Thanks again!
 
Possible ilde circuit is amiss,might need to pull ,clean thoroughly,and rebuild carbs. Whats the primer bulb doing? Is it firming up when pumped up at first start, Staying semi firm while she's running, Go over all fuel connections from pickup tube inside of the fuel tank to carbs. Has fuel/water separator been dumped into a clear container,we are looking for debris and water contamination. Have you tried pumping primer while she's running?
 
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