Running Ape

Outboard troubleshooting

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So my 8 hp Tohatsu 4 stroke is acting up and  I’m spending a few hours on her tomorrow. It is starting then quitting in 5-10 seconds. 
 

I’m going to try the following:

 

new fuel, filter, clean the plugs, and the governor. Any other ideas? 

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Posted (edited)

Not a lot of info to go on…….fuel feed is the first thing I would check. When was the last time you used it…..has it been sitting for a while? 

Edited by aae0130

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Will it rev? Restart right away? Happens when engine is hot or cold? Ambient temp or weather affect it? 

Sounds like a fuel problem. Take some starting fluid and soon as it starts to stall, spray some in. If it keeps running, that almost eliminates spark issues. I wont say fully as you could have weak spark which will ignite starter fluid but not gas. 

Will it run longer if you squeeze the primer bulb? 

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I would focus on fuel too. Doubt it is an old fuel issue because it's starting.  I'd check the pumping diaphragm.

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air - fuel - spark

Think you have the first and last covered if she's catching

 

How long was it sitting since last ran?  Was it run out of fuel, or carbs left full to evaporate?

 

In all likelihood you have crap preventing fuel flow.  When you get her to catch, put your palm over the carb face for a 100% choke.  You may be able to suck the bugger out.  Otherwise, pull and clean carbs is where I'd start.

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13 hours ago, aae0130 said:

Not a lot of info to go on…….fuel feed is the first thing I would check. When was the last time you used it…..has it been sitting for a while? 

Yes we are away for a week.

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29 mins ago, Running Ape said:

Yes we are away for a week.

one week shouldn't matter.

 

Run your tank low recently?

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Posted (edited)

i would think fuel flow first too.  not something in the engine - something in the fuel line including connections to the engine and the tank.  i’d check that before i checked anything else.

 

a buddy once took apart most of his mercury 8hp outboard for what sounds like a similar problem.  after he went back to put it back on the boat and re connect the fuel line, he realized someone had folded over the fuel line kicking it under the seat to get it out of their way.

Edited by nicknotsebastian

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I'd start by running a different tank and fuel line if you have one or can borrow one.  If the bulb is bad then you can pump in enough fuel to get it to start, but you won't maintain feed.

 

Starting fluid (ether) is also a good tool for isolating it to a fuel issue.  If you spray some in the carbs and it runs a few more seconds per squirt you know its a fuel issue.

 

sam 

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Curious how you guys are able to spray starter fluid into the carb on an 8/9.8 tohatsu 4 stroke.  The carb mounts to the engine with two long bolts that go through an air box housing thus blocking access.  I’ve watched lots of videos and haven’t seen how you are doing it.  9.9 Mercury is similar witch I wrestled with last year.

 

 

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You dont really have to get it in the carb. Spray enough into the airbox intake and itll run.

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