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Old 11-04-2016, 04:19   #1
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15hp Tohatsu Outboard Issue

Just got a 2nd hand 15hp 2stroke Tohatsu, less then 2 years old. Few days ago it started acting funny hard to start dieing when throttling. The last 2 days it would only start if throttle was in a particular position close to idle and if try to move it died could put it in gear and idle around. Yesterday we took the carb apart cleaned it cleaned all the filters and same thing. Today though I cant seem to get it started at all.

It doesnt seem to be a fuel problem and I am leaning to something with electrical or something.

Any one have any ideas?

Thanks
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Old 11-04-2016, 05:01   #2
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Re: 15hp Tohatsu Outboard Issue

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Originally Posted by deepthought View Post
Just got a 2nd hand 15hp 2stroke Tohatsu, less then 2 years old. Few days ago it started acting funny hard to start dieing when throttling. The last 2 days it would only start if throttle was in a particular position close to idle and if try to move it died could put it in gear and idle around. Yesterday we took the carb apart cleaned it cleaned all the filters and same thing. Today though I cant seem to get it started at all.

It doesnt seem to be a fuel problem and I am leaning to something with electrical or something.

Any one have any ideas?

Thanks


check the spark plugs

M.E
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Old 11-04-2016, 05:05   #3
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Re: 15hp Tohatsu Outboard Issue

They look clean and we cleaned them. could they die some other way?
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Old 11-04-2016, 05:17   #4
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Re: 15hp Tohatsu Outboard Issue

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They look clean and we cleaned them. could they die some other way?

if they are old change them, if you still have the problem with new spark plugs

try to start your outboard as normal after 1-2 pulls unscrew one of your spark plugs if it is wet from gasoline check on your carb the pilot needle screw if it is worn or out of adjustment.
the 2 stroke engines sometimes can be a headache


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Old 11-04-2016, 05:38   #5
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Re: 15hp Tohatsu Outboard Issue

Also if you cleaned the carb just by spraying it with carb cleaner, you might still have a clogged jet. Others here have recommended poking through each jet with a fine strand of wire. (I've never had to do that, but worth a try.)
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Old 11-04-2016, 06:19   #6
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Re: 15hp Tohatsu Outboard Issue

Definitely put in new plugs, too cheap and easy not to eliminate that as an issue, probably need new plugs anyway.
Once your sure it's not the carb, sounds like a clogged main jet to me, will idle but won't transition off of idle mixture to main, anyhow once your sure it's not the carb, go to the fuel pump, but clean the main jet.
All this assuming you don't have a clogged fuel filter.
Try pumping the bulb and keeping it pressurized, if its the pump, often it will run fine as your using the bulb as the pump.

How are you cleaning the carb? I have only had repeatable results by dis-assembly and soaking for a few hours in a 1 gl carb cleaner, looks like a paint bucket and has a screen basket in it, can be bought at an auto parts store, you clean it off with pure water, and blow out everything with high pressure air.
The carb cleaner in a spray can doesn't do much in my opinion.

Oh, remove all gaskets, rubber and plastic before putting in the carb soak, only soak metal.
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Old 11-04-2016, 08:24   #7
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Re: 15hp Tohatsu Outboard Issue

Follow simple procedures - is fuel getting through? Are the plugs wet? Check for spark by taking a plug out and holding against the engine block.


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check the spark plugs

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Old 11-04-2016, 08:25   #8
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Re: 15hp Tohatsu Outboard Issue

The first thing I would do is confirm if it is a fuel problem or an electrical problem.

To check if it is a fuel problem try starting it by spraying starting fluid (or carburettor cleaner) into the air intake while pulling the starting rope. (This is easier done with a helper.) No choke and open throttle. If it starts, then it is a fuel problem: carburettor issues, no fuel reaching carb, ...

To check if it is an electrical problem, unscrew the spark plug, put the spark plug back in electrical connector, and touch the metal end of the spark plug to a good, unpainted ground in the engine block while cranking the engine. You should see the spark. If not, there is an electrical issue. Careful where you hold the plug so you don't receive a shock!
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Old 11-04-2016, 08:37   #9
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Re: 15hp Tohatsu Outboard Issue

Check your fuel supply line from the fuel tank. There have been a lot of problems with the interior walls of the fuel line breaking down and plugging the fuel supply.
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Old 11-04-2016, 09:53   #10
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Re: 15hp Tohatsu Outboard Issue

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Originally Posted by Cormorant View Post
Others here have recommended poking through each jet with a fine strand of wire.
Be careful with wire. The sharp end can change the hole diameters in the soft zinc or aluminum carb body or can scratch the brass jets. Use compressed air if you have it. If not, try different sizes of nylon monofilament from your fishing kit or a bristle picked from a toothbrush or some other brush before you go to wire.

Boiling the metal parts of the disassembled carb for 20 minutes in fresh water can help clean it if you don't have the proper solvents.
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Old 11-04-2016, 09:55   #11
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Re: 15hp Tohatsu Outboard Issue

Lets all be realistic and not give "guessed" advice. First, where did you get a two year old two stroke engine? I bet it has been sitting longer.
It is a two cylinder engine, so while "new plugs" are never "wrong", they are probably not needed as it is very unlikely that both plugs, coils and/or ignition systems failed at the same time. If one fails it will usually run with a bad miss. Do at least check for fire at one of the plugs- an easy test.
Those engines have one of the best small engine carbs, but it has some very small passages and jets, and they will clog. As suggested, carb spray is often not enough to clear them.
At this point, PLEASE ask yourself if you are competent enough to SAFELY repair your carb. A local boat recently burned at the dock and injured the technician because of an attempt to repair a similar issue.
The fuel line has to be removed from the boat, complete with any filters, the ends removed, and blown clear with air. This IS dangerous!! Often it is best to replace the end fittings with new ones. It is common to have a cracked O-ring at the engine fitting that allows an air leak, which prevents the engine from sucking gas. There have also been failures with the "new" major brand fuel bulbs- they either don't seal and pump, or fail quickly. Most engines have a small internal fuel filter that is also prone to clogging. Make sure that fuel is delivered all the way to the carb when you squeeze the bulb- be very careful with the excess fuel!!
I only use the carb dip as a last resort, as it will often ruin some of the materials in a modern carb, or just "relocate" the clog. If the engine was recently running,(in the last year or so), a careful inspection and selected cleaning of the needle valve and main/idle jet assemblies will almost always fix the problem. Removing the carb and getting it on the bench is often necessary to properly clear it.
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Old 11-04-2016, 10:32   #12
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Re: 15hp Tohatsu Outboard Issue

Mostly all good advice in prior threads. Once you determine it is a fuel problem, and the way fuel is today, the additives and ethanol, attack the rubber parts and gum up small openings like never before. Anyway, once you do determine it is a fuel problem just call your Tohatsu parts supplier and ask how much a new carb is. You may be surprised at the cost - pleasantly surprised. You'd need a rebuild kit at the minimum anyway.

Time is money and you can easily burn through a ton of time chasing down a fuel problem. Just my two cents. Been lurking here for a while - good luck! Two strokes are generality great with crummy fuel - its the sitting with no use that gets any fuel system to act up.
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Old 11-04-2016, 10:44   #13
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Re: 15hp Tohatsu Outboard Issue

Make sure you've installed the kill switch!
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Old 11-04-2016, 11:59   #14
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Re: 15hp Tohatsu Outboard Issue

Good points!
A thought on the new carb. I don't fix things for a living anymore, and I do believe in protecting our air and water, but there are "issues" with factory EPA settings on marine engines. As supplied, at least some brand's replacement carbs have sealed idle settings that are too lean to work properly. The engines often start with the choke, but as soon as they get a little warm, they don't get enough fuel to run well or take advancing the throttle without a lot of missing and rough running. That pretty much defeats the "clean running" intent of the EPA.
Of course, the better solution is switching to electronic fuel injection, but since that is often not possible, other solutions must be used.
Most of the seals can and must be defeated/removed to adjust the mixture, in some cases, the idle jet might have to be drilled a size larger. Since most modern engines are usually quite well designed otherwise, they really respond well to a proper mixture and behave themselves and are a lot less sensitive to the blended fuel. Since most of us don't spend a lot of time at low idle speeds with our small outboards, I expect the environment is also better off.
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Old 11-04-2016, 12:32   #15
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Re: 15hp Tohatsu Outboard Issue

OK Had same motor, but 4 stroke.

Had same problem

Did all the above.

Turned out to be vent on fuel tank was f,,,ing closed, or really just not open enough.
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