Tohatsu 50Hp Project

[watersidemat]

Originally Posted by lukewhiting

Hard to tell what it is from the photos. Fuel oil and water mix?

At a guess. I get a lot of condensation on the outside of the carbs and this is a sludge of fuel and oil.
Can two stoke oil 'go off' in the bottle? The fuel is fresh but the oil is from 2014. Not sure what would cause the carbs to leave behind this residue.

[Roflhat]

That's old fuel. You'll need to take the carbs off and go through them all with carb cleaner, the jets will likely be blocked. I had the exact same issue on my tohatsu 50 and then Yamaha 70. When you winterise the boat you need to take the fuel line off the engine end and let the engine run until it stops. Then open the carb drain nuts to let all the fuel out. It's a problem with newer petrol, it goes all goopy when left for a while. Make sure you clean the main jets well, all the little holes will likely be blocked or get blocked as fuel gets pulled through.

[A1an]

Originally Posted by watersidemat

At a guess. I get a lot of condensation on the outside of the carbs and this is a sludge of fuel and oil.
Can two stoke oil 'go off' in the bottle? The fuel is fresh but the oil is from 2014. Not sure what would cause the carbs to leave behind this residue.

I wouldn't worry about the oil, the stuff I use is millions of years old.

[watersidemat]

Originally Posted by Roflhat

That's old fuel. You'll need to take the carbs off and go through them all with carb cleaner, the jets will likely be blocked. I had the exact same issue on my tohatsu 50 and then Yamaha 70. When you winterise the boat you need to take the fuel line off the engine end and let the engine run until it stops. Then open the carb drain nuts to let all the fuel out. It's a problem with newer petrol, it goes all goopy when left for a while. Make sure you clean the main jets well, all the little holes will likely be blocked or get blocked as fuel gets pulled through.

Fuel is.no older than a few weeks and carbs were stripped and cleaned not long ago. Engines only run a handful of times since cleaning. The fuel I drained from the bowls today seemed fine. I'll. Clean the jets regardless.as.it.doesnt take.long anyway.

[jeffstevens763@g]

Got any contamination in the tank?

[watersidemat]

Possibly. The vent on the lid doesn't fill me with confidence and when the boat moves though the water is shoots plumes of water over the top of the transom over the tank. I have a Mercury tank on the big rib I might try the lid on that and see. I do have an external water separator on the transom so that should be catching water.
Today I have raised the engine a fraction and sat it on a wooden baton I hope that will deflect some of the upsurge of water.

[jeffstevens763@g]

Could it be ethernol mixing with water giving that sludge tinted with oil?

[watersidemat]

Quite possibly. Could the carbs/venturi be letting too much fuel out and it's not all going through into the cylinders.

[A1an]

Is it more noticeable after transporting engine on boat? do you have engine tilted all the way up when towing?


Small amount of fuel can come back up the jets during transportation leaving the residue you talk about in the venturi and air box. Fuel evaporates leaving the oily mix.

[watersidemat]

Engine is down at all times. Only noticed this today after towing to the sea a spin out and a tow home.

[jeffstevens763@g]

It looks that way your engine sounds flat compared to Luke's I would defo do a full carb overhaul float needles might be worn flooding the engine if that sludge is coming through the carb Jets could be blocked, the water separator could be contaminated if water is getting in the tank.

[Rib Martin]

Now just leave it alone....[emoji12]

[watersidemat]

[watersidemat]

Originally Posted by watersidemat

Can I draw attention to part 1-21(grommet). It's a part that is not in any of the carburetors on the engine right now. I have ordered them and so have them in the house. This is from the 40/50hp tohatsu parts list. Could the absence of these grommets be causing problems. I have not seen any mention of them in the tohatsu service manual. Can anyone shed light on this part?

[watersidemat]

so behind the fuel pump diaphragm looked clean!

[beerbelly]

result

[lukewhiting]

Nice one! Did you say you've got completely fresh fuel and water separator? Something's definitely not right there!

[lukewhiting]

Originally Posted by watersidemat

Can I draw attention to part 1-21(grommet). It's a part that is not in any of the carburetors on the engine right now. I have ordered them and so have them in the house. This is from the 40/50hp tohatsu parts list. Could the absence of these grommets be causing problems. I have not seen any mention of them in the tohatsu service manual. Can anyone shed light on this part?

Pretty certain these aren't fitted to my engine

[watersidemat]

Everything in the pump carb nd fuel line/system will be new and replaced regardless of condition so there is no possible problems with that part of the boat. All new wires and kill chord fitted yesterday.

[watersidemat]

Originally Posted by lukewhiting

Pretty certain these aren't fitted to my engine

Really weird never seen them before but they are on the part diagram. Not hard to remove if it does something adverse