Clogged Carburetor Diagnosis 2007 5HP Mercury / Tohatsu Outboard Basic Maintenance

The most common problems that we see with outboard motors of all sizes brought in for service at Highland Outboards are related to carburetors. Performance issues or failure to start/run are often the result of buildup of unwanted materials in the small passages, jets, and valves inside the carb. The effects that ethanol blend gasolines have on small engine carburetors are becoming widely recognized in the industry. The buildup of residues within the carb causes all kinds of problems that can potentially ruin a good day on the water. The typical symptoms of ethanol-related carb problems are:

* Hard/Impossible to start
* Motor starts, but dies at full throttle
* Engine does not idle or run without choke

The good news is that fuel additives are available to help neutralize ethanol and prevent the breakdown of today's gasoline mixtures. We recommend the use of ethanol treatment and stabilizers every time you fill-up your outboard gas tank.

In this video we show a typical clogged carburetor diagnosis including disassembly and proof of root cause. This example is shown on a 2007 Mercury ME5M 4ST 5HP outboard, but would be very similar on Honda, Evinrude, Johnson, Yamaha, or other 4-stroke and 2-stroke outboard motors.

[johnbrianneary]

Thanks for the video. Small learning curve makes it quite easy after the first attempt. Had a gummed up carb on a 6hp Tohatsu, despite draining the bowl over winter. Cleaned the main jet with a steel wire strand, which allowed it to start. But could not idle. As there is no jet to clean, but a circuit, I left it soaking in White Spirit. Morning after resulted in a telltale mucus residue at the bottom of the container. Voilá, runs like new.

[michaeldickson]

Thanks for this video, following your principles, I managed to fix my Tohatsu 3.5 2-stroke. Nice one.

[HollywoodtoVegascom]

IT WORKED !!. it wasnt dirty at all but i cleaned it anyway, put it back and started right up. I had some questions about the black plug that fell out...didnt know where it went at first. i saw your video and it was visible...Thanks again.

[scottbrown]

agree with below- would love to see how you rebuild this carb- having the same issue on a 3.5hp version of this motor, still won't idle right. hope you do more videos soon!

[victorberner]

Excellent. Really easy to understand. Thanks. Vic

[zu]

thanks for showing this it helps me a lot.

[HollywoodtoVegascom]

awesome video...taking my motor out and trying this.
Thanks

[KendallPhillips]

Sounds like my issue. Motor only has a few hours on it and it's an 05 model. Ain't been cranked since 05. I can only get it to run on starter fluid in the carb right now. Guess I'ma bout to do what you did an then watch your next video on how to rebuild it. Mine is a Yamaha 4hp 4 stroke but it should be very similar

[sirCULTURE]

How come you never posted video showing how to rebuild this carburetor?

[tomycodd]

I had this exact problem on a Tohatsu 5HP-Had to rebuild carb with new jets.Ran engine with TruFuel before storage and filled the gas tank with non-ethanol gas.Some marinas have non ethanol fuel available.

[nando-rtmn]

really helpful video thanks I just like it

[Fishing]

Where is the video of rebuilding the carb? Great video. I have the exact same model and I think I have the problem mentioned above

[KendallPhillips]

You were right. She's running, now I gotta get the idle set, and figure out why it's not peeing

[GrandOldMan]

Did you ever make a tube - How to take the float out?

[swedishkev]

Hello mate, wonder if you can help me. I took my carburetor off and cleaned it, put it all back, took about 20 pulls and started., but it probably took time for the fuel to fill up the carb. Anyhow, I noticed your engine like mine has two black pipes missing on the carb, ? l noticed they are both missing. Just bought the motor in the summer. So l got it running, The one above the fuel pipe has just started pissing out, l assume it is fuel and not water, never checked. So if it is some overflow, its just pissing out fuel, any ideas, perhaps you know more what that pipe is and perhaps the other one, the other side on top. As l said mine are missing. Any idea whats going on ? I cleaned it all good and the float seemed fine.

[satchelrobertson]

Thanks for the video. Do you have a video on how to rebuild the float? Cheers

[spundyo]

what are the two brass inlets on top of the carbyfor? my problem is, when I prime the fuel bowl, fuel pours out of those two inlets that don't seem to be be there for any particular reason LES

[JamesNewsomeCaiLeighAnna]

Do you have the video of the cleaning of the carburetor? I couldn't find it on your channel. Thanks!

[ThomasCullen-jpfy]

My motor would start but die out after a short amount of time. Took it to repair guy who said gunk in carb . Ching-ching 150 bucks. Started doing the same thing not long after. Would run for awhile then konk out. Seemed like it's just not getting fuel to the carb. Squeeze ball would soften. Tried putting fuel tank at a higher elevation which helped a little, but still konked out. Fuel pump maybe?
Thanks.

[stuart]

I came up with a crazy idea years ago. If it has a carburetor don’t use fuel with ethanol, ever. You can get premium fuel that has ethanol so I only use 91 octane ethanol free gas. Also pump some into a jerry can or your car first to make sure the ethanol is out of the line. If you are too cheap for this then don’t use anything with a carburetor because it will cost you more in the long run anyway.