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6HP outboard engine sputtering


Mar 16, 2010
Beneteau 411 Oceanis Annapolis
...and you know what the shop will do? They’ll slap on a new carburetor and charge you for an hour or two of shop time plus shipping and the cost of a carburetor. The outboard will run like new until you neglect your fuel management again.


Feb 5, 2004
Tartan 3800 Westport, MA
If the link Gunni posted of your carb is correct, it's s brutally simple one. If it's really clean, as you say, it should be fine.

Have you checked the fuel pump?

We haven't eliminated spark, either. If the coil is marginal, it might not put out a hot enough spark at running speeds. What do the plug or plugs look like?

(I had a motor that would only idle, and it turned out the electronics module that included the coil was marginal.)
Aug 22, 2017
Hunter 26.5 West Palm Beach
You guys keep saying to clean the carb but the carb looks incredibly clean. It looked clean before I even cleaned it. Then I cleaned it, with carb cleaner. The jets were easily screwed out and cleaned. I can easily blow air with my mouth through every air and fuel line in the carb. I could before I even cleaned the carb. When I reassembled the carb I left the bowl off for a sec and sprayed carb medic through the orifices to make sure it could pass through. I haven’t tried the ultrasonic business but I’m not convinced it will help.
The external tanks fuel hose, pump, and connectors are not the problem. When I first had the issue I disconnected the external tank and put brand new gas in the internal tank to troubleshoot and make sure it wasn’t a tank issue. The problem exists regardless of what tank I use. I then took the fuel hoses inside the motor off and visually inspected them when I changed the fuel filter. I could see through them clearly and nothing was in them. At this point I am giving up and am going to bring the motor into a shop. Unfortunately that means I will have to wait 3 weeks to get it back but so be it.
Based on this information, I would check the fuel pump, to see if fuel is coming out of it. I would also check the float bowl level.
Aug 22, 2017
Hunter 26.5 West Palm Beach
Here is Adam’s carb, where is the air screw? Hint: There is none. They went away because the manufacturers didn’t want you being able to violate their exhaust gas certifications. Carbs are a dying concept for lots of good reasons, including the state of fuel composition. Sealed fuel systems are the future, Tohatsu is now selling a small outboard with fuel injection.


Part #18 is the "air jet", which is the replacement for the air screw. Changing the size of the orifice in the air jet has the same effect as adjusting an air screw. If you can't get the size jet you want, you can have any machine shop, with a thread cutting lathe, make you one. I can normally knock one out in about 10 minutes if the correct tooling is handy.
Oct 24, 2010
Hunter 30 Everett, WA
Did you mean to write "ethanol-free gas?"

You can get that, of course. It's super expensive in cans at the outdoor equipment places. Most cost-effective is CAM 10 100 octane racing fuel at about $10/gal. Sunoco Optima is available in 5 gallon pails for $95.
We have a gas station in town and our marina also sell straight gas. It's about $0.50 more in our area. Well worth it for all my small engines.

Feb 5, 2009
Gloucester 20 Kanawha River, Winfield, WV
I'll throw this out because I haven't seen it mentioned, long shot and probably too late to be of any use anyway, but an exhaust restriction can cause symptoms very similar to fuel starvation.
Sep 25, 2018
Catalina Capri 22 Capri EXPO 14.2 1282 Stony Point
I have a whole different problem with my suzuki 6 HP. It starts on the first pull and idles fine if a bit high. The trouble begins when I try to go at any speed above idle. The motor races and the prop seems to nearly stop. I am willing to buy a new motor but no one seems to have a tohatsu sail pro 20" for sale. My guess is the prop gear is stripped and needs to be replaced. Maybe over winter. Meantime, I sail as close to the marina as possible and idle in the last 100 yards or so. Have to be careful as I can't use the engine to break if I miss the cleat coming in.
Apr 27, 2010
Hunter 23 Lake Wallenpaupack
Is the prop hub spun? If so that ought to be much easier and less costly than the gears.