Tohatsu 2012 15 Hp Floods

[LindenLongRods]

Hey, engine starts, but won’t idle. Its flooding fast. Can it be gas tank?, the original has quik connect. Or if carb issue does the intake filtercome off alone or whole carb come off? What should I do? Any ideas?

 

[LindenLongRods]

So I narrowed it down, it idles when I take fuel line off. Runs a little rough and have to give a little throttle. As soon as I put fuel line back on it floods and stalls. Are fuel injectors bad? Can I put my old fuel tank with the old connector on? Why is engine drawing too much gas. Please help or ideas. engine is a dream

 

[Sea Rider]

That EPA fuel hose seems to have flooding issues specially when building too much pressure inside tank. Try out the old tank and connector, if solved the problem saty with such tank.

Happy Boating​

 

[LindenLongRods]

Tomorrow I'm going to try both ways, bypass and push the tab down in the center to see if it reseats itself, my gas can in vented so don't know if I need it or not. On different forums it's about half and half, For it and against. but if any one has any other input I will certainly take it

 

[Sea Rider]

By bypass you mean removing the middle air valve at middle hose and installing a fitting there to cancel it ? if so, try it, does the current tank vents by itself or must be operated with the air valve opened if happens to have one installed at middle cap ? Know many boaters complaining about such fuel line and tank which can balloon like a pigy before venting itself.

Happy Boating​

 

[MattFL]

Is that engine carbureted or fuel injected? You mentioned both so it's not clear. If it's carbureted, I wouldn't do anything more before cleaning the carburetor and making sure the float is working properly.

 

[LindenLongRods]

It's fuel injected with EFI, but has a carburetor. None the less, We think we figured it out with the Fuel demand valve on the fuel line. Pictured. Read up on it seems they are having problems and people are just cutting them out and getting fuel tanks with vents

 

[LindenLongRods]

By bypass you mean removing the middle air valve at middle hose and installing a fitting there to cancel it ? if so, try it, does the current tank vents by itself or must be operated with the air valve opened if happens to have one installed at middle cap ? Know many boaters complaining about such fuel line and tank which can balloon like a pigy before venting itself.

Happy Boating​

yes, home depot I bought a brass coupler, so going to try it both ways

 

[MattFL]

Glad to hear that you might have figured it out!

For future reference; do you mean it's fuel injected with a throttle body maybe? In a throttle body injected motor, in the place where the carburetor would normally be is a throttle body, which might look similar to a carburetor but is different. Inside there is the fuel injector(s). The fuel injectors could also be in other locations, but throttle body injection is one popular method.

 

[Sea Rider]

With a standard fuel line and tank with vented cap, the tank is constantly venting small gasoline fumes, with those EPA fuel lines and tank the venting will take place after the tank has released the built in fuel pressure, some say that occurs between 3 to 5 PSI ? Won't releasing small fuel quantities be comparable to releasing the same amount in one single fume shot ?

Happy Boating​

 

[LindenLongRods]

Glad to hear that you might have figured it out!

For future reference; do you mean it's fuel injected with a throttle body maybe? In a throttle body injected motor, in the place where the carburetor would normally be is a throttle body, which might look similar to a carburetor but is different. Inside there is the fuel injector(s). The fuel injectors could also be in other locations, but throttle body injection is one popular method.

I'm sure you're right, I do not know enough about this engine yet. eFI in an outboard is new to me. It does look like a carburetor Just trying to make sure it's not a electrical problem as far as like a sensor or whatever controls the gas and mixture, getting it to idle, but when get warm it's hard to maintain idle, either revs too low or too fast.

 

[LindenLongRods]

I tried again today, pushed the button down on the Fuel demand valve, it didn't reseat and the same thing happened , too much gas. Going to try without. Cut it out of the fuel line and use a coupler with vented gas cap see if there is any difference. I'll let you know. Thanks for replies so far

 

[LindenLongRods]

No haven't figured it out, but runs better without demand valve in fuel line. Still flooding or calling for too much gas. Fuel pump? it's getting gas all the way to throttle body or carburetor still not sure if fuel injected or not (I feel Stupid) best part is it runs best after you disconnect fuel line, as soon as connect runs crappy

 

[Sea Rider]

No haven't figured it out, but runs better without demand valve in fuel line. Still flooding or calling for too much gas. Fuel pump? it's getting gas all the way to throttle body or carburetor still not sure if fuel injected or not (I feel Stupid) best part is it runs best after you disconnect fuel line, as soon as connect runs crappy

When priming the fuel bulb with the stamped arrow facing up till firm, is there any fuel pills anywhere inside the motor. There shouldn't be any side effect when the line is connected or not. Maybe Paul has a tech clue as to what's happening to that motor...

Happy Boating​

 

[LindenLongRods]

It is Carburatted the Tahotsu 2012 15 HP four stroke mfs15c. The model is fuel injected. Someone has said maybe the carb needle is stuck take it apart and clean the **** out of it. Question is, does that regulate the gas flow also? It just seems way too much gas.

 

[MattFL]

OK I googled it. The 2012 model year msf15c is carbureted. Big big difference from fuel injected. Here is the manual:

https://www.tohatsu.com/marine/common/owners_manual/pdf/Toh_MFS15C_20C_003-11090-6.pdf

Now, the way a carburetor works is there's a bowl on the bottom that holds fuel. There is a float valve in the bowl to stop fuel from coming in when it's full. The float valve is a little needle, when the float rises the needle plugs a hole and stops the fuel. If the float is stuck, full of fuel, if the float needle or seat seat is dirty or damaged, etc.. then the fuel flow won't stop and it will flood. Also if the incoming fuel pressure is too high fuel might keep coming in when it shouldn't. Vent the gas can, as in leave the cap loose, and see if that helps. The vapor pressure of the gas will build up pressure in a sealed gas can. Keeping the cap loose will allow you to check if that pressure is part of the problem. That said, the motor has been sitting, clean the carburetor before you spend more time trouble shooting. A motor with a clogged up carburetor will not run right no matter what you do, until you clean it.

 

[LindenLongRods]

I took carburetor off before I left work so I will work on it Monday when I get back I will let you know how I make out,Thank you Sir

 

[MattFL]

Excellent! That should help. Focus on the little passages, small holes. Shoot carburetor cleaner through them followed by compressed air if possible. 4 strokes use very little fuel at idle so the slow speed jets and related parts have very small holes that need to be very clean. Wear safety glasses, some of the holes may squirt back at you and carburetor cleaner in the eye is bad.

 

[pvanv]

The motor is carbed. Period.
Those fuel pumps never give too much gas. Period.
The needle is not seating. Clean the carb. Properly. With overnight soak.
May need a new needle.

 

[Sea Rider]

If the float's needle is not siting and sealing well against the seat valve will see fuel coming out from upper carb but not flooding the cylinders, is that what's happening when you say the motor floods ?

Once carb has been stripped to pieces with removed float and needle check with a flashling the valve seat condition, if dirty or gunked must clean if to an immaculate clean condition for needle to sit and close at it should. Report your finding...

Happy Boating​