New to me 2020 Tohatsu 9.8 unable to go past 70% throttle, won't restart hot.

[fwman1]

Engine is on a 1436LT Alumacraft jon boat with minimal mods, very light weight. 125 lb. boat, 81 lb. engine, and I'm 170. Three gallon tank.

Seller says never had any issues at all. A little over 20 hours. Engine was last used two months ago, and supposedly had the carb run dry. Oil and foot service before purchase.

I am using my tank and fuel line from my Tohatsu 5HP. Starts and warms up as normal.
I can leave the slough, and once I get to about 60-70 percent throttle, the engine bogs down and stops. It will not throttle at all once it is restarted, and will barely idle. Bulb is not soft, and squeezing the bulb does not help it accept throttle. After about 15-20 minutes you can repeat this exact scenario. I can remove the carb drain plug after this happens and it has fuel. Spark plugs have perfect gap. The upper was a tad sooty, and the lower looked just right. Neither looked terrible.

I put a different tank and line on the engine and the behavior is the same.

Guessing either the fuel pump is toast, or the high flow part of the carburetor is clogged from sitting a couple months. I've read the carburetors on this model are sensitive to stale fuel. If that is the case, I'm not sure why it wont' restart unless it has overheated from running lean?

I'm ok doing a clean and rebuild on the carb. I used to be a jeweler, and still have my ultrasonic cleaner. Should I order a carburetor rebuild kit and a gallon of carb cleaner, or is there a fuel pump test I can try first?

Thanks for any and all replies.

 

[Scott Danforth]

If you're still under warranty, take it to the dealer

 

[fwman1]

Thanks for the response. I believe I will need to get the original owner's proof of purchase to go that route. I saw where the 5 year warranty would not cover instances where the fuel system is compromised by poor gas, or stale gas.
I've never had to get warranty service from Tohatsu, so I have no experience with how strict or lenient they are regarding warranty work.

Would it be worth the effort to soak the carb in Berrymans dip, blow it out with compressed air and retry?

Sunday, so I suppose I'll reach out to the Tohatsu rep in the area (35 miles away) tomorrow.

 

[Scott Danforth]

Take carb apart and soak

Warranty should be transferable

 

[fwman1]

Yep, Houston we have a problem. Looks like the carb bowl was not drained, and some ethanol fuel must have been in the mix. I think when I started it, it probably sucked a bunch of gunk down in the jets. Of course, it may not have been run dry either, and the jets were clogged when I got it. The float was not impeded, but there were signs of the gunk in the upper part as well.

I have a gallon of Berrymans' and an ultrasonic cleaner. Can these rubber and plastic parts hold up to an hour in the Berryman's solution in my ultrasonic cleaner? Should I order one of the rebuild kits and replace all the rubber? This is a 2020.

Again, thanks for helping the noob!

 

[Scott Danforth]

They should. Use some monofilament line to make sure the passages are clear

 

[pvanv]

Yeah, there's a lot of trash in the carb. set the rubber bits aside and ultrasound overnight. flush the fuel pump too. After the soak, I usually blow out all passages with generic carb spray.

 

[km1125]

Also, when you're blowing out carbs with air start with the ENGINE side of the carb passages. You want to blow debris back towards the air inlet or the carb bowl, rather than trying to force debris further into the carb where it might never come out.

 

[fwman1]

Great advice gentlemen. I was able to complete the cleaning and reinstallation by the evening today. I'm pleased to report the engine now runs great, as the original owner had said. Turns out time flies, as he checked and it had last run in early April.
This is a great forum. Everyone is very professional and helpful!
Thank you so much from a two Tohatsu guy now.

 

[MattFL]

If your 9.8 is similar to my 6, running it until it stops does not fully empty the carburetor. You need to open the drain on the bowl to get it empty, then pull the rope so it sucks whatever is in the jets out. It's possible the previous owner ran it until it stopped but didn't drain the bowl. If you really want to store it well, remove the pilot jet screw and hose in some fogging oil. And avoid ethanol gas if possible.