I got four non-vehicle motors that ALL needed service: lawn mowers (John Deere, walk-behind); 40 hp and 2.5 hp boat motors. I'm talking over a grand for non-starting! Culprit: old gas left in each most likely the problem that screwed up the carbs. Granted, I used Sta-bil in gas cans and in tanks of all four (something I found not advisable for use in 2- and 4- stroke motors. Annual storage lasts 5 mos. with gas sitting in each carb. My boat motor and lawn mower mechanics said the same thing: gum and varnish in the carbs preventing gas flow. Now I know to run the gas out of each and dump any gas-can gas into my cars and truck. (I don't know how to empty the gas in my snow blower unused for up to 9 mos.)
One very frustrating and very expensive repair was done by four shops on my 2.5 hp Merc 4-stroke - three of which took my money and didn't repair a thing! Finally after a year, I not only found why the motor wouldn't start, but how to start the motor by NOT following the owner's manual. The manual said to:
1. pull out the choke knob
2. open gas tank vent
3. open gas flow knob
4. put throttle handle in start mode
5. pull the cord
Here are the instructions printed on the handle:
![[Image: IMG-9848.jpg]](https://i.postimg.cc/1VF9X99f/IMG-9848.jpg)
Even after all the expense, which included many round-trips miles away to each shop with my truck, the motor started only out of the water, but even then, most of the time wouldn't restart.
My mechanic didn't have a clue. He said it started for him and proved it with the lower unit in a tank of water. On the boat and in the water - nothing!
Okay, you would think at least one boat motor mechanic would have put together some reasons for what I described. Don't hold your breath! I had to go online to find the possible causes. Here we go:
A 2.5 Mercury outboard motor, particularly a 2-stroke model, can be difficult to restart in the water, sometimes even more so than on land. Possible reasons:
1. [font="Google Sans", Roboto, Arial, sans-serif]Water in the Exhaust Housing[/font][font="Google Sans", Roboto, Arial, sans-serif]:[/font]
Note: one piece of advice my mechanic gave me: for better starting, use only fresh, non-ethanol, high-octane gas in the 2.5 hp 4-stroke. Improved gas mileage is also an advantage.
Note: the same mechanic said that gas stays in the carb even when not running for a time and choking it when restarting it is usually not necessary but may lead to flooding if the choke knob is pulled half way like the instructions say. (see photo)
Note: I spoke with someone about the best oil to use for either the 4 or 2 stroke motors. He stated use only marine-grade oils meant for each. 2 for 2; 4 for 4.
He agreed that non-ethanol gas is best, always dump unused gas but before that to add Quickstore to the gas in the tank to clean carb before running dry.
[*]Note: the great source for the above information once I gave him the serial #:
[*][font="Open Sans", sans-serif]Boat Prop Warehouse 920-788-0220 - svc extension[/font]
[*]
As of yesterday, the motor runs fine. I still have to run it in the lake on the transom to see if it starts and restarts. But after all the expense and frustration, I finally found what was needed to maintain the motor and keep it running. Guess I won't trash the motor after all. To buy a new one cost over $750 - less than it took to repair it!
One very frustrating and very expensive repair was done by four shops on my 2.5 hp Merc 4-stroke - three of which took my money and didn't repair a thing! Finally after a year, I not only found why the motor wouldn't start, but how to start the motor by NOT following the owner's manual. The manual said to:
1. pull out the choke knob
2. open gas tank vent
3. open gas flow knob
4. put throttle handle in start mode
5. pull the cord
Here are the instructions printed on the handle:
Even after all the expense, which included many round-trips miles away to each shop with my truck, the motor started only out of the water, but even then, most of the time wouldn't restart.
My mechanic didn't have a clue. He said it started for him and proved it with the lower unit in a tank of water. On the boat and in the water - nothing!
Okay, you would think at least one boat motor mechanic would have put together some reasons for what I described. Don't hold your breath! I had to go online to find the possible causes. Here we go:
A 2.5 Mercury outboard motor, particularly a 2-stroke model, can be difficult to restart in the water, sometimes even more so than on land. Possible reasons:
1. [font="Google Sans", Roboto, Arial, sans-serif]Water in the Exhaust Housing[/font][font="Google Sans", Roboto, Arial, sans-serif]:[/font]
- When restarting in the water, the exhaust housing (the section between the powerhead and the lower unit) fills with water.
- This creates back pressure, making it harder for the engine to reach the required RPM for the ignition system to function properly.
- For engines with magneto capacitance discharge ignition (like some Mercury 2- and 4-strokes), a minimum RPM is needed for the flywheel magnets to generate sufficient voltage for spark.
- Outboard carburetors can flood easily, particularly in 2-stroke engines.
- Over-choking or improperly using the choke, especially when trying to restart, can contribute to flooding.*
- A strong fuel smell around the engine is a tell-tale sign of flooding.
- Other causes of flooding include:
- Float system problems: damaged or mi
justed floats can lead to excessive fuel entering the carburetor bowl.
- Needle valve issues: worn or stuck needle valves can fail to shut off fuel flow.
- Fuel pump problems: excessive fuel pressure or leaking diaphragms can cause flooding.
- Stuck choke plate: a choke that remains closed or partially closed can create a overly rich fuel mixture.
- Float system problems: damaged or mi
- 4. Other Potential Issues:
- Fuel system problems: Old or contaminated fuel, clogged fuel filters or fuel lines can disrupt fuel flow.
- Spark plug problems: Dirty or worn spark plugs can prevent ignition.
- Electrical issues: Problems with the ignition coil, safety lanyard, or kill switch can hinder starting.
- Compression issues: Low compression can prevent the engine from running.
- Fuel system problems: Old or contaminated fuel, clogged fuel filters or fuel lines can disrupt fuel flow.
- Important Note: Repeatedly trying to start a flooded engine can worsen the issue and potentially damage the engine.
Got it after all the expense and B.S.!
So, the motor stayed outside on a stand for over a week getting ready for the trash when I decided one last time to try starting it. But get this: I didn't notice the choke was all the way in and I pulled the cord. IT STARTED AND RESTARTED, though not in WATER! and with the choke all the way in - something counter to the owner's manual. I put the motor in water and restarted it, letting it run at the lowest idle speed. IT DIDN'T STALL ONCE! I did this for 3 consecutive days, early morning with air temp at 70 and mid day with air temperature near 90 degrees. Started every time and idled without stalling once and with THE CHOKE position unchanged -ALWAYS IN!
Note: one piece of advice my mechanic gave me: for better starting, use only fresh, non-ethanol, high-octane gas in the 2.5 hp 4-stroke. Improved gas mileage is also an advantage.
Note: the same mechanic said that gas stays in the carb even when not running for a time and choking it when restarting it is usually not necessary but may lead to flooding if the choke knob is pulled half way like the instructions say. (see photo)
Note: I spoke with someone about the best oil to use for either the 4 or 2 stroke motors. He stated use only marine-grade oils meant for each. 2 for 2; 4 for 4.
He agreed that non-ethanol gas is best, always dump unused gas but before that to add Quickstore to the gas in the tank to clean carb before running dry.
[*]Note: the great source for the above information once I gave him the serial #:
[*][font="Open Sans", sans-serif]Boat Prop Warehouse 920-788-0220 - svc extension[/font]
[*]
As of yesterday, the motor runs fine. I still have to run it in the lake on the transom to see if it starts and restarts. But after all the expense and frustration, I finally found what was needed to maintain the motor and keep it running. Guess I won't trash the motor after all. To buy a new one cost over $750 - less than it took to repair it!
