2.5 hp Mercury starting problems

senkosam

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First off I paid too much for the motor. Second, I trusted the name. I had no idea that the motor would be difficult to start after the first time without following specific guidelines - namely: do not choke or the motor will flood. When the motor floods, the gas is trapped with nowhere to go and must evaporate to disappear. Single-cylinder motors have the same problem starting if not done correctly. Of course, the owner's manual says nothing about starting a cold motor started less than an hour before.

All of the above is the advice and facts given to me by my outboard motor mechanic. The first time I brought the motor to him, parts inside the carburetor were melted because the bucket of water I was trying to start the motor in didn't have enough water in it. The job cost around $200. The second repair was for the same thing though I forget what I did wrong. That cost around $300 to fix.

I'm afraid to try the motor again on the lake, worried it won't start after the first time resulting in me rowing a mile back to the launch. :(
 

airshot

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I have the same model but older 2.2 hp model. Starts on second pull unless I do something wrong. Cant blame the motor for your own faults and not following instructions. Yes...it can be quite expensive to learn some lessons, I am sure we have all done it !!! If the carb is set up properly, and compression is good, starting should not be an issue. These little motors are made by Tohatso and have a very good reputation from my research. Mine is an awesome little motor !! I use it on my 12' jon boat and as a trolling kicker on my 16' side console. Runs for almost 6 hrs on a gallon of gas....dead idle can be a little shakey being a single cylinder, but up at half throttle where I troll at it is quite smooth. I think your motor needs a good thorough go thru to get " everything" set up properly !! If you have to much invested then consider it a life lesson and look for one in better condition..
 

senkosam

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The motor was bought this year and hasn't been used except for a few outings where it wouldn't start the second time. No fun having to use the trolling motor to get back to the launch 1/2 mi. away. I was told to not choke the motor even after 30 minutes and that it should start. We'll see.
 

Lowrider1

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I have the old 3.3 hp Merc and the first time each Spring or whenever the first start of the season happens I shoot a short squirt of "starting fluid" in the direction of the carb and it starts easily and thereafter all Summer. I think there must be an accumulation of oil or gunky stuff (not further identified but may come from the corn being burned in the E10 gas) that is on the spark plug while sitting for months and the starter fluid does just the right thing to get an adequate spark to get things working. Worth a try.
 

senkosam

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Will consider using starter fluid. Have yet to put in Stabil for the winter.
 

DaleH

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... the owner's manual says nothing about starting a cold motor started less than an hour before.

To start a flooded OP, close the choke so it is OFF. Open the throttle full, wide open and crank. That'll dump the fuel out and she should start within a full pulls.

All of the above is the advice and facts given to me by my outboard motor mechanic. The first time I brought the motor to him, parts inside the carburetor were melted because the bucket of water I was trying to start the motor in didn't have enough water in it. The job cost around $200.

IMHO you need both a new mechanic and to get your $$ back .... he raped you!

I've never seen melted parts in a carb, from over-heating, as low water for the OB would result in the powerhead getting hot due to lack of cooling water. To then get a carb hot enough where its internal parts melted, the powerhead would have to have been glowing red hot. The only thing I can think of is that someone did use a ton of too aggressive starting fluid and that solvent 'dissolved' the parts. IMHO starting fluids should never be used in OBs.

If a powerhead overheats you can blow a head gasket. Look around the head for evidence of leaks. A warped head could leak and you lose compression, which makes starting hard, if not possible. A slightly warped head cover can be fixed by a DIY'r, when reinstalled with a new gasket.

The second repair was for the same thing though I forget what I did wrong. That cost around $300 to fix.

Ouch ...

VERY sorry to hear you have these issues! $500 on top of a motor you already bought ... hurts! If you were nearby I'd fix it for you ... for free.

Please make SURE you have the proper sparkplug and that it is gapped properly. That is typically the easiest thing to check/fix that can cause hard starting. Good luck!
 

senkosam

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Wish we lived closer. Will try your full throttle open next time - maybe this week at the lake. Thanks for your input.
 

Stand Up

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First off I paid too much for the motor. Second, I trusted the name. I had no idea that the motor would be difficult to start after the first time without following specific guidelines - namely: do not choke or the motor will flood. When the motor floods, the gas is trapped with nowhere to go and must evaporate to disappear. Single-cylinder motors have the same problem starting if not done correctly. Of course, the owner's manual says nothing about starting a cold motor started less than an hour before.

All of the above is the advice and facts given to me by my outboard motor mechanic. The first time I brought the motor to him, parts inside the carburetor were melted because the bucket of water I was trying to start the motor in didn't have enough water in it. The job cost around $200. The second repair was for the same thing though I forget what I did wrong. That cost around $300 to fix.

I'm afraid to try the motor again on the lake, worried it won't start after the first time resulting in me rowing a mile back to the launch. :(
I'm not sure what happened to screw the whole thing up, but maybe try one on these next time you start the motor out of water.
 

airshot

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Check your compression before trying the motor again. No sense going further if compression is low. Then find another mechanic, or learn to do these things yourself. Many bad mechanics have turned people away from boating and motors, when they try to pull the wool over folks faces !!!
 

airshot

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How to check compression?
A compression tester is needed, fits in the spark plug hole, turn engine over 3-4 times then read the gage. Look up compression specs forb that engine and compare to your gage.
 

senkosam

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Dale. you're a peach of a guy and the information came in very very useful!!!
And guess what, it worked like a charm!!!

I started the motor and let it idle in a high bucket full of water, shut it down and 10 min. later started it again - no choke. It was laid on the ground (with handle up as the manual insisted), remounted and tried to start it again - again no choke. No go.

Then I followed your suggestion and put the throttle at near 1/2 and BANG! it started on the first pull!!! I let it sit for 2 hours in the rain with vent cap closed, opened the cap and it started with 1/4 throttle on the first pull and every time after after that. The rpms at idle were at minimum with an even put-put, with water going back into the high bucket. No choke at all for any restart after the very first start.

Too bad the Merc manual said nothing about the throttle used to increase air flow for restarts and not use the choke once started and run for a few minutes. The tiny restart band on the throttle was nowhere near enough for what was needed to restart after 30 min.
Also, good thing I don't need to put in non-ethanol gas as the manual says. A fuel stabilizer should be enough - right? Non-ethanol gas is over $4/ gal.!

Now, if only you could suggest a way to avoid the backache lifting the 50 lb.s on and off the transom and into the truck bed!!!

Thanks everyone for your suggestions. At one time or another, in a few years, I will need most of them.

If I hadn't got it started, I was considering a 5hp, 48v electric motor, but I couldn't find 48v batteries that weren't double the cost of the motor. The battery weight alone would have killed me!
 
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richg99

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Dale is a VERY smart guy. I listen to him.

It's funny that many outboard motors have their own little idiosyncrasies. Once learned, they behave.

I had a 50 hp Johnson that wouldn't start without simply tilting it back a bit. My mechanic explained how gravity and the carburetor system that to work. Duhhh.
 

senkosam

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It's funny that many outboard motors have their own little idiosyncrasies. Once learned, they behave.
So so true!
This is the first gravity-feed gas motor I've ever owned, my previous motot a 90hp with an external tank that is primed using a squeeze bulb. Bet the motor starts this morning minus choke. If not, no choke from then on restart. Too bad the wind will be a problem today. I'm dying to zoom across the water given the small hp limiting going on-plane LOL.
 
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airshot

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Wow 50 lbs ?? I have the 2.2 hp 2 stroke that only weighs 30 lbs...mine runs like a top.
 

DaleH

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A typo???? ( … on the 2.5 weight)

FYI, if that 2.5hp has a ‘restrictor plate’ behind the carb, check to see what the same vintage 3.5 or 4hp models use for a restrictor plate. I’ve turned many a 2 to 2.5 into a higher HP motor by this simple change.

But ALWAYS go by model numbers and double-check to make sure they both use the same carb assembly!
 

senkosam

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If I found out that info, I wouldn't know what to do with it. The guy who fixed the motor ain't cheap and he's the only one that would be able to install the new part. Again, thanks for the help and I too wish we lived closer!
 

Texas Prowler

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These little mercs are a breeze to work on. Very simple motors. I got my 4hp not running, then used a ball hone to deglaze the cylinder. Installed new piston rings, Chris Carlson Reed valves- behind the carb and a 5hp carb. Runs like butter. Easy job. All you need is the will and a socket set.
 

senkosam

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All you need is the will and a socket set.
....and the skill and experience to go with it!
I do routine maintenance on my John Deere riding mower and small mower - same thing for my 1995 Silverado, but that's it. Beyond that, I pay the very high cost of repairs i.e. the 2.5hp.
 

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