Outboard help?

[Renae]

My 4 HP Tohatsu 4 stroke (MFS4C) ran like a top all summer, but cut out on me in an awkward spot while entering a marina last week.  I could restart on one pull, but it would quit again after a few seconds.  Fortunately I was close enough to limp in this way.  Switching from the external to internal tank didn't change the misbehavior.

I took the boat back out 2 days ago, and the symptom persists, but it was a great day and the winds were blowing out from the launch, so getting in and out without a motor wasn't tough.

I realize that this must be a fuel problem, but I've never dissected a carburetor before, and I'm not sure that's the first step anyway.  I want to sail another month yet this season. 

How would you approach this if it happened to you?

[crazycarl]

i have a 2010 4hp tohatsu and had the same problem since day one.  it was cheaper to have the carb replaced than rebuilt.  less than $200. 

[Bob23]

Renae:
  This is probably a shot in the dark but worth mentioning. This past summer I experienced the same thing but it turned out to be a fuel line connection at the motor that was she culprit. My fix was simple: remember to push the fitting all the way in! Duh. I doubt your fix will be that simple but maybe the fitting on your fuel line is bad? Maybe.
  Happy sailing! I plan to sail well into October, best sailing season here in NJ!
Cheers!
Bob23

[wes]

My 5 hp Tohatsu/Mercury has always been prone to these inconvenient work stoppages. It's usually due to clogged jets in the carb. They are so tiny that the tiniest spec of debris will ruin your day. I've learned to filter every drop of fuel and to keep a close eye on the fuel hose and fittings.

Wed

[carry-on]

Was the cooling water spitting out when the motor quit? Impeller or gear oil.
Was the red light flashing when it quit? Could be low oil?
Is the fuel filter clogged?
Good spark plug/connection?
I would check these areas before delving into the carb, because I have no luck fixing these little carbs!

[slode]

Does this happen when at low speed only or even when revved above 1/4 throttle?  The idle/low speed passages in these carbs clog easily, but can be blown out with carb cleaner by removing the screw on the top side of the carb and spraying carb cleaner down through that hole.  If it will run at high throttle then stall out when you let it off that's the first thing to do.  If it dies at higher throttle then it's fuel supply through the main jet, either from fuel line like Bob23 stated, or from a plugged seat or main jet which you need to pull the carb and float bowl to get at.  It's an easy job if you just make sure everything goes back the way it came apart.  $200 is a lot to spend on a replacement carb.  I've never spend more than 45 minutes removing a carb, cleaning, and re-assembling it on an engine like this.  If you're going to own small carbureted gas engines this is something you are inevitably going to want to learn

[Bob23]

Ethanol is the bane of our small outboard motors existences! I've been using E-Zorb water remover in my gas for years and I haven't had these kinds of problems. I also use premium fuel.  My biggest problem is me forgetting to hook up the fuel line!

https://www.amazon.com/Amazon_MDR-MDR574-ZORB-WATER-10/dp/B07KN5BWLH/ref=sr_1_15?hvadid=78615134223189&hvbmt=bp&hvdev=c&hvqmt=p&keywords=ezorb&qid=1569441177&sr=8-15

Cheers!
Bob23

[brackish]

Random thoughts:

These Carbs are very simple, only three places of possible trouble, two jets and a float valve, don't be afraid of taking it off and cleaning it.  I'm sure someone has done a youtube on it.

The Jets can clog with gunk and have to be cleaned, the float valve can stick either open (bypassing leading to flooding) or closed starving for fuel.

Fuel always gets blamed, but there is no real air filter only a pig catcher.  If there is any source of fine dust it can clog a carb.  Dirt dauber nests built in the cowl can do it, don't ask me how I know.

I used my boat yesterday and overnight.  It has the six hp Tohatsu/Nissan sail pro.  It started on the second pull and ran for an hour out to my anchorage.  Then an hour back this morning.  It had been sitting for two weeks when I started it.  Prior to that it had been sitting for three months.  Same two pulls.  It has been this way for the four years I've owned it.  The only time I've had a problem is with the aforementioned dirt daubers and it took me two cleanings of the carb to get back from that.  You can bet I check for them every time I go to the boat.

My protocol is different than most advise.  I NEVER run it dry.  I NEVER disconnect the fuel line unless I'm adding fuel.  I use non ethanol gasoline with a spot of SeaFoam.  If I haven't run a tank down in a six months or so I put it in my truck and start fresh.  I'm running two of these small carb motors on that protocol, one on the sailboat, one on a skiff and have no trouble with either (as long as I keep the dirt daubers at bay).

[Zephyros]

My Tohatsu 4HP starts on the first or second pull everytime, I recently cleaned and rebuilt the carb with the Tohatsu carb kit and replaced the fuel pump as it was gunked up as well from the previous owner using Ethanol fuel.

Here is my recipe to beat stale fuel:
http://cpyoa.geekworkshosting.com/forum/index.php?topic=11276.msg85213#msg85213

Defender has the Tothatsu carbs for a good price:
https://search.defender.com/?expression=Tohatsu+Carberator&x=0&y=0

I ordered my misc parts from:
https://www.boats.net/
and
https://www.tohatsu.us/

[Renae]

Was the cooling water spitting out when the motor quit? Impeller or gear oil.
Was the red light flashing when it quit? Could be low oil?
Is the fuel filter clogged?
Good spark plug/connection?
I would check these areas before delving into the carb, because I have no luck fixing these little carbs!

Impeller working—first thing I checked.

No oil light.

I think I'm back to a fuel delivery problem.

[Renae]

Does this happen when at low speed only or even when revved above 1/4 throttle?  The idle/low speed passages in these carbs clog easily, but can be blown out with carb cleaner by removing the screw on the top side of the carb and spraying carb cleaner down through that hole.  If it will run at high throttle then stall out when you let it off that's the first thing to do.  If it dies at higher throttle then it's fuel supply through the main jet, either from fuel line like Bob23 stated, or from a plugged seat or main jet which you need to pull the carb and float bowl to get at.  It's an easy job if you just make sure everything goes back the way it came apart. 

During my first misadventure, I actually escaped the rock piles by getting it to run at very low throttle, which would still kill when I opened it up.

$200 is a lot to spend on a replacement carb.  I've never spend more than 45 minutes removing a carb, cleaning, and re-assembling it on an engine like this.  If you're going to own small carbureted gas engines this is something you are inevitably going to want to learn

I totally agree that $200 for a carb that may or may not fix the issue is not going to happen.  As for the "If you're going to own..." part, I agree that if I were in for the long haul with this motor, I would need to get comfortable with the fuel system.  I'm not in for the long haul though.  My plan was to limp this motor along for a year or two then buy a Torqueedo.  I'd be fine doing that now, but I don't want to miss a single day on the lake setting that up as October creeps in.

[Renae]

I do disconnect my fuel tank when I trailer.  The quick disconnect doesn't always seem to click on as crisply as it should.  I did think of that, but I'm not sure why a bad tank connection on the external would make a difference when I switched to the internal tank.  It seems to me that the problem has to be something that the tanks hold in common.

[slode]

From the fact that it will run at idle tells me it's not the idle/low speed carb circuit.  If it bogs and dies immediately when you open the throttle it's a plugged main jet.  If it revs but dies after a few seconds its a plugged seat, both of which are commons with either tank supplying it.  That means pulling the carb and cleaning those parts out or putting in a carb kit.  If you have any friends around that know even the first thing about carbs they may be able to help.  I typically charge a 12 pack for a job like this...

All the suggestions about non-ethanol fuel, using stabilizer, and not running it dry I agree with.

[bruce]

Renae,

Sorry you're having OB problems. I can relate, my Lehr 2.5 and Honda 2 have been reliably problematic all summer. Fortunately, a friend lent me her Torqeedo 1003. It has it's own issues, but fuel isn't one of them. Power wise, a 1000 W motor (3HP) is fine for a PC, hull speed is reached at about 70% throttle. It's all about battery capacity. Not sure which Torqeedo you're thinking about.

If you do decide to go electric, in a couple of years, or sooner out of frustration, give the ePropulsion line a look. The Spirit 1.0 is a direct competitor with the Torqeedo 1003C, and the newer 1103C. I took delivery on one this week. I like it better than the Torqeedo, although not so much that I'd replace the Torqeedo if I owned one already.

This UK dealer sells both, and has done a nice comparison. On the PC, the larger motor housing on the 1103C may not play nice with the rudder.
https://nestawayboats.com/shop/e-propulsion-spirit-1kw-electric-outboard/

Plugboats has a guide on electric motors in this range.
https://plugboats.com/electric-outboards-less-than-5-kw/

The ePropulsion Navy 3.0 is a 6 HP equivalent. Battery pack alone is $3K.

I know Mike, and others, like their trolling motors. Plugboats did a guide for them as well.
https://plugboats.com/electric-trolling-motors/

[Renae]

Bruce,

I'd love to hear more about your ePropulsion motor as you get a feel for it.  I have mostly been thinking about the Torqueedo 1003 for my Suncat, and it's nice to know there are alternatives. 

The decision can happily be delayed a bit longer—I took apart the carburetor on my Tohatsu, sprayed the heck out of everything with carb cleaner, doing the same to the fuel filter and the connectors for good measure. I put everything back together and the motor runs.  Hopefully that will get me through October. 

My biggest concern so far based on casual online reading concerning the Torqueedo—and it appears to be similar for the ePropulsion—is the length of the tiller.  On the Tohatsu, I can angle the tiller up over the top of the transom, so the distance from the transom to the back of the motor mount can be shorter.  I don't know if that makes sense, and I haven't even gotten to the point of making measurements, but I doubt that using the Torqueedo with a remote and fixed steering would be satisfactory.   Too much loss of maneuverability.

Back in business, I hope,

Renae