2016 8HP Tohatsu only runs on choke.

[baconbiscut]

A little bit of back ground, I use this motor every couple of months but mostly it sits in the garage. After each use I flush and run until it starves of fuel then I put away. I store the engine upright on a stand. Recently I went to start it up since I get home once a month for a few days, it ran and Idled then died. After that I could only get it to start and stay running on choke. So I thought that maybe the jets were clogged, so I removed the carb and pulled it apart, I blew everything out and still the same symptom. The gas I was using could be a problem because it has been sitting for sometime, but I also think that this could still be a carb issue. I took it apart and put it back together in a hurry so maybe I didn't find the problem.

I want to know if I'm heading in the right direction with, or if maybe I'm overlooking something

Dan

 

[ondarvr]

If it runs with the choke on it means the carb is still dirty, there are many small passage ways that can easily plug up.

​Running the motor until it stops doesn't drain the carb, it only lowers the fuel level in the float bowl, it helps a little, but the dried out fuel can still plug things up.

 

[pvanv]

ondarvr is 100% right. If it runs better with choke, it's too lean. Running the carb down is good preventive procedure, but US fuels are still pretty dirty these days, and residue can restrict the ultra-small passages in the carb. Proper cleaning involves a complete disassembly (including jets and emulsion tube nozzle), a 4-hour soak of all non-rubber bits in carb dip, followed by a liberal blow-out with generic spray carb cleaner. Then a careful reassembly, paying attention to float height.

 

[baconbiscut]

So last night I pulled the carb again and did a thorough cleaning. There was some gelled up fuel in the bowl, but what I did notice was lots of water in the fuel. I I soaked the jets for about and hour and blasted with compressed air, I did this for the rest of carb and passages on top as well. The passages in the jets are tiny! I put it back together and its running like the day I got it new. Putting it back to together I did not pay attention to the float height, what is the spec for that? I guess I should purchase the shop manual so I have all of that information.

My concerns at this point are I'm an OTR truck driver and my boats tend to sit unused and not started for about month or two at a time, sometimes longer. I have a two stroke Mercury that never gives me trouble like this, I'm guessing because it has bigger jets that don't clog as easily. Last time I put the Tohatsu up I ran it out of fuel but did not treat the fuel that sat, I've since drained the tank and have added stable. Is it suitable to leave the carb bowl full now that I've treated the fuel? Or should I pull the drain plug to the bowl each time I store the motor to go back on the road. I don't think running the motor out of fuel completely drains the carb

Thanks, Dan

 

[pvanv]

Yes, older, non-EPA motors had bigger, shorter passages... that didn't clog as easily.

Running it out helps a lot, but to be thorough, use the drain if storing for a few weeks or longer. No, stabilizer helps with fuel "rotting" but does not prevent it from evaporating and leaving residue in the carb. Since you had water and gel in the system, that indicates water intrusion, or E10 gathering water from the atmosphere in the long term. Fuel should always be less than a month old; You can dump any leftovers in the car to use it up.

The float should be parallel to the carb casting when the casting is inverted. It's seldom wrong, and that float is not designed to be adjusted, so if it's wrong, a new float is called for.

 

[baconbiscut]

Okay Paul, thanks for your input. I'm gonna dump the rest of the fuel into my pick up while it sits and drain the carb bowl. Next time I have the carb apart I will check that the float is parallel with the casting. I appreciate everyone's help.

Dan

 

[isaksp00]

When I have symptoms like that on my 8hp Honda it has always been the low speed jet. On the Honda it can be unscrewed from the top of the carb. I push a very thin plastic "wire" through the jet and spray with carb cleaner and the idle starts working. I run it dry after each use but do not drain the bowl.