Tohatsu 25HP MFS25B FI need battery to run?

[bigcountry11]

I had a loose ground to my battery while crabbing the other day. 15ft War Eagle 2005 MFS25B outboard in the Chesapeake bay. I couldn't get the bolt tight. I had to mess with the wire going to neg terminal to get the boat to start. When I ran it, it felt like I had half power. I thought it was the macks river runner I put on the skeg. It sputtered when at full power.

The oil lamp acted normal. Didn't stay on or anything. Do you think the loose connections to neg terminal could cause this? I guess after researching, this could be limp mode where it runs 2800RPM max?

Also, had other issues that need noted. Bay was rough and I had a lot of water come over the stern (since I was the only person in the boat. Probably 40gallons. That means the battery terminals got wet. So much so, I was getting slight zap when trying to tighten down the neg terminal with a leatherman since my feet was in water. (yes that much water).

 

[pvanv]

The MFS 25/30 does not need any battery to run. That is one of their selling points: digital CD ignition with only the internal alternator. You can pull start without even having a battery aboard. However, it is not good to short out the battery cables; that could cause problems. Did the warning horn sound at all? Low speed ESG could trigger for over temp, low oil pressure, or MAP or temp sensor being beyond normal range... but I would expect the beeper to sound as well. Does the beeper sound for a few seconds when starting?

 

[bigcountry11]

Only a sound once. But didn't hear anything after that. And that was when it was first in the water. Just went out and ran in a bucket. Seems to run like a champ, but of course can't put in gear and run, so who knows.

Do you have to reset anything to get out of this ESG mode? I know it ran at only 10mph or so even before I got things wet.

I would imagine a 25HP would push a 15foot jon faster than 10MPH. Its only been in the water twice. About a 2004-06 vintage. First time, it seemed to run great. Not as fast as my old 25HP two stroke evinrude, But I figured thats because its a 4 stroke.

 

[bigcountry11]

Thanks so much for replying. by the way.

 

[pvanv]

The beeper should sound at startup, then go silent. Sounds like the ECU (computer) didn't detect anything wrong. The ESG (governor) resets when you turn off the motor. You may have a spun prop hub. Do you have a spare prop to try?

 

[bigcountry11]

Thanks again for the reply. But if I had a spun prop hub, wouldn't it rev real high?

 

[pvanv]

Usually, but if it's just a bit mushy, it can soak up a fair amount of power without a lot of high RPM. I would try it again, now that you can pick your conditions, and aren't potentially ingesting a lot of water into the motor's air stream.

 

[bigcountry11]

Bought a new prop. When I got the motor, it had a broke skeg. They guy said it didn't have a mark on the prop. But after investigating, its not the original prop. So I ordered a new DS10 and a hardline tach to see what RPM I have.

 

[bigcountry11]

Well, gave up, took it to the shop. They say it has very dirty fuel injectors. He said it should make a world of difference.

 

[pvanv]

The hardline tach may not work correctly on the 3-cylinder motor. If you want the best life from the injectors, be sure to run good gas, and at the end of the season, drain the vapor separator and let the motor stall from lack of fuel to reduce the amount of gas being "stored" in the fuel system. If the injectors were really dirty, cleaning or replacing them will make the motor almost like new..