140 Tohatsu Alarm

I have not been on here much as my motor has never given me an ounce of issues. The other day I headed out for a day of scouting and everything was in check. Ran for about 30 min at cruise then pulled the throttle back and eased of to a bank to have a look. Went to power back up to cruise and the motor sounded the alarm and would not let me exceed 2500 RPM. Pulled the throttle back and checked everything out. Good stream of water, oiling properly (light smoke at idle), head was not hot, and running well under 2500. We ran 2000 RPM for another 15 min then I decided to try and power up and off we went. Ran another 30 min and pulled back to about 23-2400 RPM for a few minutes and went to power back up and it did the same thing. This time I pulled it back to idle and shut down. Waited about 10 sec and cranked it back up and it was fine. We headed back to the ramp after this and pulled it out. I figure it is a sensor of some kind going bad to tell it to go into limp mode or something to that effect. the only thing I can think that I have done is spray the motor down with corrosion block 2 trips before. Any ideas? It is a 1998 model. Thanks in advance.

Re: 140 Tohatsu Alarm

Temp sender, low oil sender or water pressure sensor. Or, bad ground, loose wire, defective ignition switch or buzzer. Or actual overheat, actual low oil or demonic possession.

Or you might have just picked up an obstruction over the water intakes that then floated off. If you haven't done a water pump kit replacement in over two years I would urge you to consider it before you spend time trying to check all the other possibilities.

Re: 140 Tohatsu Alarm

TOHATSU GURU said:

Temp sender, low oil sender or water pressure sensor. Or, bad ground, loose wire, defective ignition switch or buzzer. Or actual overheat, actual low oil or demonic possession.

Or you might have just picked up an obstruction over the water intakes that then floated off. If you haven't done a water pump kit replacement in over two years I would urge you to consider it before you spend time trying to check all the other possibilities.

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I just replaced the impeller. I bought a whole water pump kit but it was quite a bit different from what was on mine in the form of gaskets and metal wear plate and cup. The impeller was the same so I put the new impeller and woodruff key in. When it was doing this I checked the head with my hand and could leave my hand on there for a while and the oil is full. I also checked the (what I call the exhaust box) on the side of the motor by the head and it was only warm to the touch. Do these sensors work on resistance? if so do you know the values that are within parameters? I have an outboard jets lower unit so I think I can rule out pickup obstruction as the way it is setup the impeller actually forces water to the water pump then up to the motor. Thanks for all the help.

Re: 140 Tohatsu Alarm

You need to get a service manual to get the test procedures and values. Or you can contact tohatsu at info@tohatsu.com and their service department will direct you.

Re: 140 Tohatsu Alarm

TOHATSU GURU said:

You need to get a service manual to get the test procedures and values. Or you can contact tohatsu at info@tohatsu.com and their service department will direct you.

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Thanks I will find a service manual and start there.

Re: 140 Tohatsu Alarm

OK got a manual tested all sensors and they check out. Went out yesterday and ran great the first 30 min or so then I did notice my pee stream getting a little weaker in a no wake zone and the limp mode started again, got to where I was fishing and had it shut down for about an hour, when I cranked it back up it was back to normal, what could be causing it to slowly loose water pressure as time goes? It is odd, after it sits for a while it is fine.

Re: 140 Tohatsu Alarm

"I just replaced the impeller. I bought a whole water pump kit but it was quite a bit different from what was on mine in the form of gaskets and metal wear plate and cup"

Wrong impeller probably.

You should have put in a 3C7873221M...Chances are you used the impeller out of 3B7873221M which looks the same...And isn't. Get a new 3C7873221M kit and replace the liner and wear plate and then try it again.

Also, what dealer screwed up and sold you the wrong kit?

Re: 140 Tohatsu Alarm

TOHATSU GURU said:

"I just replaced the impeller. I bought a whole water pump kit but it was quite a bit different from what was on mine in the form of gaskets and metal wear plate and cup"

Wrong impeller probably.

You should have put in a 3C7873221M...Chances are you used the impeller out of 3B7873221M which looks the same...And isn't. Get a new 3C7873221M kit and replace the liner and wear plate and then try it again.

Also, what dealer screwed up and sold you the wrong kit?

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I ordered another kit and it is the 3C7 kit and the wrong one. I ordered it off ebay as the picture was my set up. The company sent me the 3c kit and it was the same one I started with and the wrong one. Here is the link
http://cgi.ebay.com/ebaymotors/ws/e...0135151500&viewitem=&sspagename=STRK:MEWNX:IT

The one pictured is the one I need but the one that was sent was the above referenced 3c7 part number (which apparently is what the computer says is needed.) The 3c7 kit comes with no gaskets and an o-ring for the housing, the wear plate only has one slot in it, and the cup has a rolled lip on 1/2 of it. I need the 2 gasket, 2 groove wear plate, and a smooth lip cup. I am getting frustrated as I want to get my boat up and running. Thanks for your help.

Re: 140 Tohatsu Alarm

If you have a 140 then the correct kit is a 3C7873220....It's not an opinion it is a fact. So, either you don't have a 140 or the kit they are sending you is not a 3C7873220(regardless of how it is marked). Your best bet would be to order the kit from someone else.

Re: 140 Tohatsu Alarm

TOHATSU GURU said:

If you have a 140 then the correct kit is a 3C7873220....It's not an opinion it is a fact. So, either you don't have a 140 or the kit they are sending you is not a 3C7873220(regardless of how it is marked). Your best bet would be to order the kit from someone else.

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I am starting to wonder with the outboard jet on it if they used a 90 3b kit. Everything I can see would appear to be from a 90 hp kit. Does the 90 kit have 2 gaskets and a smooth lip cup?

Re: 140 Tohatsu Alarm

Tohatsu does not make a jet unit so the problem lies with the jet manufacturer. If you have a jet unit from California Jet it is probable that they adapted a 90 hp water pump. That means you would use a 3B7873220M water pump kit. Basically, anytime you have something designed and built non OEM you can run into WTF issues.

Re: 140 Tohatsu Alarm

TOHATSU GURU said:

Tohatsu does not make a jet unit so the problem lies with the jet manufacturer. If you have a jet unit from California Jet it is probable that they adapted a 90 hp water pump. That means you would use a 3B7873220M water pump kit. Basically, anytime you have something designed and built non OEM you can run into WTF issues.

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Yeah I have a Outboard Jets jet. I have put a call into them to see if they used the 90 HP pump. Is the 90 and 140 driveshaft the same size?

Re: 140 Tohatsu Alarm

The diameter at the pump is the same on the drive shaft, but different drive shaft, housings and water pump parts. IE The impeller will look like it fits the shaft, but is incorrect. Basically you have the opposite of what I first thought was the problem(140 hp and trying to put on 90 hp parts). You have a 90 hp pump and have been trying to put on what would normally have been the correct 140 parts. I'm sure the 90 water pump kit will solve the problem for you.

Re: 140 Tohatsu Alarm

TOHATSU GURU said:

The diameter at the pump is the same on the drive shaft, but different drive shaft, housings and water pump parts. IE The impeller will look like it fits the shaft, but is incorrect. Basically you have the opposite of what I first thought was the problem(140 hp and trying to put on 90 hp parts). You have a 90 hp pump and have been trying to put on what would normally have been the correct 140 parts. I'm sure the 90 water pump kit will solve the problem for you.

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That is what I am starting to think.

Re: 140 Tohatsu Alarm

The 90 kit can be found at the link below.

http://www.internetoutboards.com/partdetail.asp?id=131

This kit does not come with bolts or a new key as they have switched over to a chrome system rather than the old SS.

Re: 140 Tohatsu Alarm

TOHATSU GURU said:

The 90 kit can be found at the link below.

http://www.internetoutboards.com/partdetail.asp?id=131

This kit does not come with bolts or a new key as they have switched over to a chrome system rather than the old SS.

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OK got the right pump and put it together still a no go. I did notice that is was pumping fine until I got up on plane and the stream got a little weaker but no alarm. Slowed down to idle then went to plane off again and boom alarm and limp mode. Here is the strange part, I reversed hard then tried to take off again and it went with no alarm. Repeted those steps with the same result. I brought it home and put some hylamar (it was the only thing laying around) between the jet pump and the water pump spacer block thinking it was getting air once on plane. Took it back to the launch and the exact same results. Am I missing a step? I have never had this kind of problem before.