2.5 hp Mercury starting problems

Texas Prowler

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Try swapping the spark plug. You need to get used to starting the outboard at home in a barrel or trashcan water for a few days.

Learn when to choke and not to. That's key with these.

Use the choke at the wrong time and it'll flood

When on the water I always try starting without the choke first. At least a few times.
 

senkosam

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I did start it at home in a bucket of water. For three straight days it started with no choke and a bit of throttle. Bet it will start today.
 

senkosam

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It started right up mounted on the saw horse in a large bucket of water - first time no less and no choke - just a bit of throttle! Three consecutive starts after that - no problem plus a low even idle. Again - no choke.
I can't figure out why it wouldn't start yesterday. It's back in the truck waiting for another test run - of course with a trolling motor mounted just in case. Rowing a mile into a 15 mph, chilly wind IS something to sneeze about. Must have gone threw half a box of tissues!
 
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Lowrider1

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I would be comfortable with 6-8 hp on a boat that size, but that’s just my opinion and on the waters I frequent.

Wind, tides, weight and oncoming inclement weather (lightning in a tin boat is no fun) can all play a part in the decision for me.

My 12’ mirrocraft was set up for two people plus gear and while my 9.9 was ok and fun enough, I really wanted a 15 hp on it.
I went from a 9.9 2 stroke to a 15 4 stroke Merc on my 12' Duroboat...much nicer than the 9.9...only mistaker was not getting elec start...$300 more and 8 lbs if I recall. Older I get the more I like push button things...especially on my blender.
 

Rumblejohn

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I went from a 9.9 2 stroke to a 15 4 stroke Merc on my 12' Duroboat...much nicer than the 9.9...only mistaker was not getting elec start...$300 more and 8 lbs if I recall. Older I get the more I like push button things...especially on my blender.
When I was in high school, my hunting buddy had a 12' Featherlite aluminum semi-V with 25hp Chrysler on it. The old Popular Mechanics magazines had an ad with a girl in a bikini hold one up with one hand. It was definitely a car top boat. When loaded with us (400 lbs), (400 lbs of dogs and gear) it was an interesting experience of the St. John's River at 3:00am. When you made a mildly sharp turn there was a 1-3 second delay of the bow banking after the stern. Needless to say it led a short unhappy life. My friend passed from cancer in 1988, but it was a miracle that either of us survived adolescence. My advice is a 9.8 or so will be fine as long as you are not too crazy with it.

John
 

RaisedByWolves

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It started right up mounted on the saw horse in a large bucket of water - first time no less and no choke - just a bit of throttle! Three consecutive starts after that - no problem plus a low even idle. Again - no choke.
The solution should be clear at this point.

Take the bucket of water out on the boat to ensure easy starts.
 

DaleH

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Hey, how do you store it when you put it in the pickup truck? Maybe you should make a simple wooden stand to transport it straight up and down, like when mounted on the boat.

That might improve the starting … my brother had a small little Honda that if he put it on its back or on its side … it would never start up again for a couple days.
 

airshot

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If you have a fuel shutoff valve, be sure to close it and run the carb dry of fuel. I always do this before taking the motor off for transport. I never open the fuel valve until the motor is upright and ready to run.
 

senkosam

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The motor is leaning against the seat at a 45-degree angle with the handle up like the manual stipulates. It started 5x on the water and every time off the water on the 1st or 2nd pull. Something happened on the water trying to restart it after the 5th time. Using the choke guarantees the motor will not start; giving it some throttle guarantees it will start. Regardless, I will have the 55# thrust Minn Kota along to return to the dock when no restart is possible.

(Never had to drain the carb for transport but will for winter storage.)
 

DaleH

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Keep in mind we’re all just trying to help you out …

But regardless, OB motors are like women … YOU gotta find out what THEY want in order to ‘turn them on’ …
 

airshot

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You might try a hotter spark plug, all your stories appear to be fouled plugs or plug...one cylinder. I have had brand new plugs that were crap, so you may have a bad or weak plug. Also try jumping the plug wire to the plug, you should be able to jump a 3/16" gap, if not you could have a weak spark from the ignition. No matter what, as a boater of 60 plus years, I always run any OB with a fuel shutoff until the carb is free of fuel !!! That shut off valve is not there for decoration.....
 

senkosam

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Keep in mind we’re all just trying to help you out …

But regardless, OB motors are like women … YOU gotta find out what THEY want in order to ‘turn them on’ …
This morning, 4 tries / 4 instant starts - never needed the choke.
 
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cyclops2

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Old Carb engine CAN BE VERY FLOAT HEIGHT SENSITIVE. Test is warm up motor while tied to the dock. Then at idle in FORWARD GEAR. Tilt the motor to SLIGHTLY different angles and hold for 15 seconds at each position. Tells if carb needs to have float / mixture screw better adjusted.
 

senkosam

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Then at idle in FORWARD GEAR.
?? The boat goes forward.

Tilt the motor to SLIGHTLY different angles
It's the last thing I did before putting the motor into storage. Have to wait until spring of next year to see if it starts and restarts.

Thanks for the suggestions.
 

cyclops2

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The smaller the engine ? The more important a CORRECT sized fuel filter is. See if the engine even has a thermostat. Cold engine WILL WILL blacken sparkplug's FAST and cause hard to start engine. I always put in a sparkplug 1 heat range hotter than specified to help with starting & trolling reliability.

NEVER ASSUME the spark plug is the correct one !!!!!!!!!!!!!!!!!!!! Find out FOR SURE ! Then buy a new one & carry a new one & sparkplug wrench. Also buy A sparkplug gap checking tool. Check and adjust the thick heavy metal curved part until the gap is correct. .........NEVER touch or bend the center rod of the spark plug.
 

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