Help us before my husband throws our Mercury outboard in the water!
- Thread starter SVMusic
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- liveaboards mercury outboard
I think this update may be important, Cara. It makes it clear your problem is dependent on engine temperature. The basics of all these engines are you have to have fuel, spark, and air. I see you've gotten excellent troubleshooting guidance here in this post for these basic requirements, some considering temperature. But at another diagnostic level what your 2-cycle must also have is compression. Decent compression for a "cold" engine can fade badly as the cyl. head and block get hot if you have loose head bolts, bad piston rings, cracked cyl. head, scored cylinders, valve clearance changing with warmup, etc. Root cause might have been poor engine cooling but now more permanent damage as a result.Update:
Changed the plugs and cleaned the filter.
Just like it has been in the past, motor started up, and ran well and got up on a plane. Then after 10 minutes, it dies if you accelerate. This happens time after time, seemingly after the motor warms up. After it cools, it can be started again. Rinse and repeat.
Suggest you get a compression tester at any auto parts store, pull the plugs and do a compression test on your cylinders cold and then again hot after the engine stalls out again under load and time. Or, even easier, note the pull force required to turn over the engine with the pull starter: i.e. "feel" the cyl compression resistance as you slowly [not enough to start it]rotate the crankshaft cold, then do that again after it heats up and fails.
That's an interesting theory, but I think unlikely that you'd have sufficient compression for the motor to run well, and then bog down when warm.
By then, @SVMusic didn't mention, I don't think, if cooling water was running? Maybe it's just overheating.
(BTW, these don't have 'valve clearances to worry about, it's a two stroke with reed valves.)
An engine needs air, fuel, compression, spark, and an unobstructed exhaust. The latter could cause bogging down, but unlike to change with temp.
I am betting it's the electronics module. I had one fail on one of mine.
By then, @SVMusic didn't mention, I don't think, if cooling water was running? Maybe it's just overheating.
(BTW, these don't have 'valve clearances to worry about, it's a two stroke with reed valves.)
An engine needs air, fuel, compression, spark, and an unobstructed exhaust. The latter could cause bogging down, but unlike to change with temp.
I am betting it's the electronics module. I had one fail on one of mine.
Buy a can of SeaFoam, watch several SeaFoam YouTube videos, and do an intensive engine fuel treatment. Had I done this 2 years ago it would have saved me $1,000 in multiple carb services.
That's generic stuff, I was asking @Monterey385 what it was that was fixed for him by Seafoam.
Maybe I should quit this, lest I hijack this thread into a gas additive debate. Suffice it to say I'm skeptical.
Y
yeah, I get ya. But those are pretty much all seafoam might fix.
Better living through Chemistry...but that isn’t this. Lube and carbon removal is not the issue.
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Happens all the time on 2-cycle dirt bikes - compression fade. So, we'll see how Eddie and Cara or their mechanic resolve this.
That said, I agree its much more likely it loses spark due to faulty Mercury ignition "switchbox" failing at temperature. That's what I think kloudie meant by coils and trigger in his post last Thursday which Cara and Eddie responded to with interest. Yet no joy yet? Maybe they've not pulled a plug and checked for the blue spark on the hot engine yet.
Agreed, but the coils and trigger are separate parts. And, those could fail as well. I am biased, having had a switch box fail. (Maybe two? I found my order and I have purchased one for each engine back then.)
Truth is I’m not sure myself ... and i never push brands on this board ... but earlier in the post the OP indicated the carb was serviced and others suggested it might need servicing again ... since this worked for me I figured I’d share.
We have used seafoam several times and change the spark plugs too. The baffling part is it just doesn't seem consistent. But we will not quit! The motor will not go in the water! Haha
This, along with many of the awesome suggestions in this forum, have really helped us in our quest for a solution. I myself really appreciate the description of the engines mechanics. Every little bit helps and this post was very helpful!
Makes sense. I'm a "root cause" kinda guy, i like to find the smoking gun and correct the issue. I am not a big fan of additives. I always found it curious to read of guys using ethanol-free gas and then dumping Seafoam into it, which is up to 25% alcohol.
Cleaning these carbs is not so hard. And, I mean, I have the exact, same motor as the OP. The real show-stopper issues I've encountered, in nearly 20 years with them, are failed electronic modules, failed fuel systems (OEM tank,) and dirty carbs.
Other things (for complete honesty!):
I would be amazed to hear of anyone doing everything that is required for proper ongoing maintenance, which would include scheduled replacement of hoses and other rubber parts, proper lubrication, partial tear-downs, inspection of wear items, and so on. Despite this, they keep going until they succumb to something like this - a dirty carb, torn fuel pump diaphragm, failed electronic module, etc.
Cleaning these carbs is not so hard. And, I mean, I have the exact, same motor as the OP. The real show-stopper issues I've encountered, in nearly 20 years with them, are failed electronic modules, failed fuel systems (OEM tank,) and dirty carbs.
Other things (for complete honesty!):
- seized lower unit - failed seal, salt water sat in it over the winter;
- failed water tube seal - no cooling water circulating;
- steering friction device stiffens, requires disassembly, cleaning, and grease;
- broken nylon nut on engine pivot;
I would be amazed to hear of anyone doing everything that is required for proper ongoing maintenance, which would include scheduled replacement of hoses and other rubber parts, proper lubrication, partial tear-downs, inspection of wear items, and so on. Despite this, they keep going until they succumb to something like this - a dirty carb, torn fuel pump diaphragm, failed electronic module, etc.
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