Power Loss in Tohatsu 5HP Outboard

[Inthewind]

Well I guess I was right for once,coil packs, ignition coil, same thing in my book. Glad you finally figured it out.

[SkiprJohn]

Aloha Sean,

Whoopee!! You got her fixed. Congratulations. Just remember, its always the last place you look!! That's a quote from my wife.

Kind Regards,

JohnL

[GordMay]

Originally Posted by SkiprJohn

Aloha Sean,
Whoopee!! You got her fixed. Congratulations. Just remember, its always the last place you look!! That's a quote from my wife.
Kind Regards,
JohnL

Which suggests that your wife is wise enough to quit looking, once she finds “it” - a policy to which I (being lazy) also try to adhere.

[ssullivan]

Yes, thanks to everyone who played the game. And a special thanks to InTheWind who is our winner! ha ha

If anyone has Tohatsu questions, please send them my way. I'd be happy to share any of the little tidbits I picked up.

[towns03]

Sullivan! I need expert guidance-

I have the same motor (i think), 5hp 2-stroke. this rig is missing just the last 1/4 of it's power and it's just barely keeping me from getting on a plane. my fuel system and carb are spotless. I've disassembled them completely and don't see problems. My next step would be the ignition coil based on this thread BUT the local dealer says he's never seen that problem and doesn't think that's the problem...

How did you come to your conclusion and what should I look for when examining the coil/plug for problems?? The dealer didn't have any ideas for me!

Thanks!

[towns03]

to elaborate a bit, I ran my rig for an hour+ yesterday and didn't have the juice to get on a plane except for 5 minutes near the end of the trip. just as randomly as the power showed up, it disappeared and I was back to pushing water....

[Inthewind]

Usually when a coil goes bad, it will start acting up when it gets hot after the motor reaches full operating temperature. Have you changed your spark plugs? If not change them. Dump your gas into a five gallon bucket to make sure there is no water in it,if there is water, it will be on the bottom. Run non ethanol marina fuel. If you have a hard bottom inflatable, make sure there is no water in the hull adding weight,could have leaked in if the plug is not sealed tight. Is the motor missing? or does it seem fine but will not reach full power?

[Boracay]

What sort of dinghy does a 5hp Tohatsu get on the plane?

[towns03]

there's no water in the system. Since the problem started i've taken the tank and the carb completely off the motor for inspection. I get my gas from a standard gas station here (Houston). is that a problem??

my boat is a West Marine Zodiac with an inflatable keel. the max rating for this boat is a 8hp...

so the fact that it's not working when it's cold cancels the possible problem with the coil? I've changed the plug already and it didn't help.

[motion30]

I just had a simiular problem with a 5 hp nissan (same motor) Bought a carb rebuild kit including the parts for the fuel pump $40 Cleaned tank and fiter cleaned and rebuilt the carb and fuel pump Runs great now and will plane a 9' hard bottom with just me at 175lb

[Inthewind]

Depending on how old your fuel hoses are (newer fuel hoses are rated for ethanol fuel) older fuel hose can be compromised sometimes causing the inner lining of the hose to collapse therefore restricting fuel. I have seen ethanol fuel turn some rubber into a jelly like substance. Also your fuel pump on the motor I believe has a rubber diaphragm,if that has been compromised from a small hole or crack in it,you will have a weak fuel supply. Also caused possibly by ethanol fuel. Not sure if those are your problems but worth checking out.

[JEdward]

I see your original Tohatsu 5hp post was in 2007. But I wonder if you could share the final solution? We are now on mooring ball in Marathon, and yesterday our Tohatsu 5hp 2-cycle started misnehaving badly. It will start OK, idle OK, and rev-up in neutral OK. But, as soon as we put it in forward, it dies? I have taken off fuel lines and the carb and cleaned thoroughly. Water flow through shaft is good. Do you, or anyone else on the Forum have any ideas? Any/all comments will be appreciated. Thanks.

[JEdward]

P.S. Working from phone and did not/could not find more of original post thread. Now found a bit more, and someone mentions a diaphragm in the Tohatsu 5hp? Was that a factor. Still cannot get to part of thread that explains your solution, however. Again, thanks.

[motion30]

Todays fuel causes many problems especially in small out outboards The carb needs to be disasembled to cleaned. I use a single wire strand to rod out all jets and air bleeds.

[JEdward]

To: motion30
Thanks for your direction this a.m. Have followed instructions, including wire, and, sadly, now have become more intimate with Tohatsu 5hp M5BS than I desire to be with all but a few things in my life! Not particularly the way I wanted to spend day. Worse, no success. Removed needle valve (don't know name of part) to clean. Now can't seem to get fuel mix on it adjusted? I put new glass side fuel filter in line, as double check, no obvious water or dirt there. Now, engine seems to run only long enough to burn fuel hand-pumped in from tank? Very frustrating. Any other ideas will be appreciated. Anyone know where to get Toatsu 5hp M5BS service/repair manual?