Problems with Tohatsu 50hp

sam12345 · 27 August 2009, 14:33

I have a (roughly 2005/6) 2 stroke 50hp.
Took it out today for the first time in about 2 months and run okay. Went out for 15-20mins and then lost nearly all the power and the engine died. Obviously restarted a couple of times and reved niced and high then everytime i put it into gear i could only get very low rpm and power.
Then after a few times lost power all together.
I usually put a rag in the back to soak the water up but forgot today and it was pretty rough. So i put it down to water and ran the usaual checks for water in the carbs etc etc none was found.
Anyway got it back on land and it ran right up to high rpm even in gear then after a few seconds/minutes died. Check the spark plugs which seem okay could get a few more runs out of them. As i say no water in the carbs and decided id take her home to be looked at.

Got home and she runs but will only start on very little throttle and choke and wants to die at first i kept her running by opening up a little but after a while opening the throttle killed it quicker.

Anyone who can give me a list of things to check would be much appreciated.

Jizm · 27 August 2009, 16:40

Fuel starvation?
Check all your hoses, and tank vent etc.

sam12345 · 27 August 2009, 17:45

Quote:

Originally Posted by Jizm

Fuel starvation?
Check all your hoses, and tank vent etc.

Fuel through the primer, filter and carbs so thats not a problem.
Someone has suggested the bottom fuel pump may have gone, got to check a couple more things first.

Jizm · 27 August 2009, 17:57

Bottom fuel pump?
the diapragm may have split, think the pump is on the port side, near the tray.

sam12345 · 27 August 2009, 18:19

Quote:

Originally Posted by Jizm

Bottom fuel pump?
the diapragm may have split, think the pump is on the port side, near the tray.

Thats exactly what they said.
Ive checked all the plugs and the bottom one seems no wetter than the other two cylinders. Apparently this would be a sign of the fuel pump being buggered.

Downhilldai · 27 August 2009, 18:22

Try running it while pumping the primer bulb. This will effectively take over from the fuel pump. If it runs ok when you do this, then the fuel pump may well be faulty.

sam12345 · 27 August 2009, 18:29

Quote:

Originally Posted by Downhilldai

Try running it while pumping the primer bulb. This will effectively take over from the fuel pump. If it runs ok when you do this, then the fuel pump may well be faulty.

Nice one ill try this in the morning the neighbours wont appreciate me running it now with them having a kid and all!

Jizm · 27 August 2009, 18:47

pop the cover off the pump, the diapragm is easily checked.

sam12345 · 27 August 2009, 18:50

Quote:

Originally Posted by Jizm

pop the cover off the pump, the diapragm is easily checked.

I pressume it will be easily noticeable and cause a suction leak right?

Jizm · 27 August 2009, 19:06

the damage will be easily noticed, ie ripped or holed...

sam12345 · 27 August 2009, 19:35

Quote:

Originally Posted by Jizm

the damage will be easily noticed, ie ripped or holed...

Okie dokie nice one ill check that tomorrow.

sam12345 · 28 August 2009, 17:44

Bizzare!
Just went out checked the lines etc everything seemed okay, started her and primed her, she stalled, started again primed for a bit and she ran fine so i thought... fuel pump diaphragm but stopped priming she ran fine.
High rpm... fine, in gear... fine, in gear high rpm... fine.
Only iffy thing was the tell tale took a while to run through but then i have only got one sided muffs on and had a play and got it pumping.

Now all i did yesterday was took the fuel pump cover off and the bottom carb off, drained the carbs and thats about it.

Jizm · 28 August 2009, 18:06

Quote:

Originally Posted by sam12345

Bizzare!
Just went out checked the lines etc everything seemed okay, started her and primed her, she stalled, started again primed for a bit and she ran fine so i thought... fuel pump diaphragm but stopped priming she ran fine.
High rpm... fine, in gear... fine, in gear high rpm... fine.
Only iffy thing was the tell tale took a while to run through but then i have only got one sided muffs on and had a play and got it pumping.

Now all i did yesterday was took the fuel pump cover off and the bottom carb off, drained the carbs and thats about it.

you may have dislodged the crud that was causing the problem, you need to try it under normal operating conditions to be sure though.

sam12345 · 28 August 2009, 18:13

Quote:

Originally Posted by Jizm

you may have dislodged the crud that was causing the problem, you need to try it under normal operating conditions to be sure though.

Thats the thing im worried about.

Jizm · 30 August 2009, 06:21

Tried it yet? Any luck?

sam12345 · 30 August 2009, 15:17

Quote:

Originally Posted by Jizm

Tried it yet? Any luck?

I probably wont be able to test it for a couple of weeks now but will at first chance.
I had the carbs off and gave them a real good clean. The fuel pump was fine and no build up or anything in the carbs.
Getting some new plugs when i get chance and will see how she goes when i take her out next.

sam12345 · 06 September 2009, 19:02

She seems fine now, i think either water or crud in the carbs.
Thanks for the help guys.

Jizm · 07 September 2009, 05:31

No worries, glad it's sorted