Mercury 50hp wont turn over

[dlandersson]

I had that problem after sitting all winter. Used Seaform and after a few trips/uses no more problem.

Tried starting it up today without the lower unit on. With the motor in neutral it turns over no problem but will not start. I pushed the throttle advance button and put the throttle up. Motor starts almost instantly. I backed the throttle down to about where I think it should idle (by sound) and it runs great. If I push the throttle back into the neutral position it dies. I'm assuming their is something that is suppose to advance the throttle while in neutral that isn't currently working possibly? The bigger issue is it is leaking gas from somewhere behind the carbs. I pretty good drip is going. Thinking their could possibly be a float stuck open. I also noticed the fuel lines run behind there, but they are impossible to see.

[Mcadieux]

Pulled and cleaned the carbs. They weren't the worst I have seen but the jets were definitely all clogged. After Reassembling the engine runs a bit rough but does start and run at idle. Gonna replace the spark plugs and run a can of seafoam through. Both the air intake and mixed with gas. I greased the hull out of the impeller and put the lower unit back on, still starts and runs without an issue. I used every piece advice given and it looks like it all worked great.

My next question is I was running the motor on a pair of muffs. I was getting a decent stream of water out the tell. I noticed the water got very hot very quickly. Within maybe a minute and a half of running at idle the water is hot. Is this normal? I'm worried its heating up way to fast. Worried about a possible oil pump issue.

[Tomfoolery]

My next question is I was running the motor on a pair of muffs. I was getting a decent stream of water out the tell. I noticed the water got very hot very quickly. Within maybe a minute and a half of running at idle the water is hot. Is this normal? I'm worried its heating up way to fast. Worried about a possible oil pump issue.

I can't speak to what's normal for a Mercury, but I consider it normal for my Honda. At least, it was until I enlarged the pee stream hose and removed the tiny fitting at the discharge end. That pee stream bypasses the thermostat, just like the old-school car engine water pumps and thermostats, which sent water to the cabin heater without regard to the engine thermostat status.

You can also stick you hand in the discharge at the prop (take the prop off first, please, and leave it in neutral) to see what kind of temperature it's discharging.


But if the thermostat is really old, or you don't know how old it is, I'd replace it. Easy, quick job, and brings much peace of mind.

[taylormade]

My next question is I was running the motor on a pair of muffs. I was getting a decent stream of water out the tell. I noticed the water got very hot very quickly. Within maybe a minute and a half of running at idle the water is hot. Is this normal? I'm worried its heating up way to fast. Worried about a possible oil pump issue.

I may have missed it but did you say what year this Merc is? 2 stroke/4? Some of the Mercs circulated through the cooling system and some bypass it and dump before it ever gets to the t-stat.

I'm with Tom, my Honda gets hot within a minute or two for sure, but my 115 Mercury four stroke bypasses the engine completely and is really just a notifier that the water pump is working.

[Tomfoolery]

In fact, that's how I knew my thermostat was bad last spring - the pee stream was cold, almost as cold as the hose water into the muffs. It was stuck open, so the engine wouldn't get up to temperature, at least not in the driveway. Replaced it, and it got warm/hot in a matter of a couple of minutes, tops.

[sailboatmike]

My Merc tell tale runs warm on the muffs but cold when actually in the water, I presume we are just not putting enough water in when using the muffs to keep it cold, anyway when running on the muffs we want the thermostat to open so we can give the whole thing a good flush out.

Glad to see you got the motor running, we bought our boat cheap, this allowed us to write off the motor if it was knackered, alas the Engine Control Unit was only running it on one cylinder and we couldnt see value in spending $500 for a new ECU for a 20 year old motor, so we bought a newish low hour (10 hours claimed) 75Hp

[Mcadieux]

My Merc tell tale runs warm on the muffs but cold when actually in the water, I presume we are just not putting enough water in when using the muffs to keep it cold, anyway when running on the muffs we want the thermostat to open so we can give the whole thing a good flush out.

Glad to see you got the motor running, we bought our boat cheap, this allowed us to write off the motor if it was knackered, alas the Engine Control Unit was only running it on one cylinder and we couldnt see value in spending $500 for a new ECU for a 20 year old motor, so we bought a newish low hour (10 hours claimed) 75Hp

Its a 4 Stroke motor, and it sounds like my heat issue was normal. On the muffs the flow out the tale is kind of inconsistent, I need a better pair of muffs. I bet it will run colder once I get it in the water. We boat this boat really cheap with the same plan to write the motor off. I only paid 7k for the boat and motor. Both looked like they just came from the factory. It was a 2000 26x and the guy was original owner. It had been in covered storage for at least 8 years. Based on the evidence I have found I think it was in storage from 2003. Guy was beyond rich and 93 years old, the boat was at one of his 6 houses. House had never even been lived in. 1.7M dollars and guy never even moved in.

[sailboatmike]

Wow you did REALLY well a 2000 26X, you wounldnt want to know what that boat on a good trailer would sell for in Australia (between $30,000 and $36,000Au)

I thought I did well when I paid $20,000Au for my 1995 with a suspect motor, I have NEVER seen one here for that cheap before and I imagine it will be a VERY long time before I see one at that price again, all up she may owe us around $30,000 but with the bigger motor, new sails and refurbished cushions I recon she would be going up in value