Tohatsu 90 hp tldi all 3 tach lights blink on

[Danjae]

I have a Tohatsu 90 TLDI bought new in 2004.

My engine had been running a bit rough at troll so replaced the plugs and added a can of seafoam to the tank before the last trip. Went out yesterday and the engine sounded perfect all day until while heading back to the dock from grouper trolling I had all three tach lights flash at me and the engine knocked itself back to idle speed. It had happened once before a couple years ago and the guys on this board......Shoes and the very helpful guy from Tampa told me it was probably a loose battery connection and that was it, problem solved. In that incident it was intermittent. Yesterday once it flashed I could not get the boat to go above 2800 for more than a few seconds before it kicked in. Checked the connections and they were tight.

I looked at old posts here from others and did see where the battery is supposed to be 1000 CCA......mine is only 720 cca but the battery is new, couple months old, in fact it is two new batteries the 720 hooked together with a 500 cca batt for reserves. I know the terminals and batt connections are bright and shiny as I just cleaned them when I put the two new batteries in. ( I Replace the batts every 2 years if they need it or not) Even though the batt is not a 1000 it has worked fine up till this point. I had sprayed corrosion X on the terminals just before this last trip but don't see why that would matter. I will check the wires connecting to the batts today to se if there is any corrosion under the shrink wraps at the connections. Can you even check the wires on the motor? I looked and could not see where they were even accessible.


I do not have a manual but will be picking one up as this is my first out of warranty problem.





Why is it if you have a dead battery and get a jump start at the dock and start the engine you can then motor away and the low voltage thing does not happen?

Does disconnecting the battery reset the TPS and ECU or just that kill switch procedure?


I did not know the TPS ECU reset procedure yesterday, could that be what the problem is?

Thanks all in advance for any suggestions or advice on what to look for that could be the culprit.

 

[pvanv]

Re: Tohatsu 90 hp tldi all 3 tach lights blink on

If the battery voltage raises to an abnormally high level, all 3 lights will flash and engine speed is limited to 2800-3200 range.

 

[rcl700]

Re: Tohatsu 90 hp tldi all 3 tach lights blink on

You can get to the motor connection be removing the plastic fly wheel cover
4 small bolts I think you will see them in the box area infront of the fly wheel.

Hope that helps.

As for the lights. Mine were all flashing and I found a bad spark plug.
After replacing lights went out.

 

[Danjae]

Re: Tohatsu 90 hp tldi all 3 tach lights blink on

You can get to the motor connection be removing the plastic fly wheel cover
4 small bolts I think you will see them in the box area infront of the fly wheel.

Hope that helps.

As for the lights. Mine were all flashing and I found a bad spark plug.
After replacing lights went out.

Didn't the motor run badly with a bad plug?

 

[Danjae]

Re: Tohatsu 90 hp tldi all 3 tach lights blink on

Well I bit the bullet and replaced the almost new battery with a 120 ah 1000cca and will take the boat for a ride today and see if that fixes the issue.

 

[Danjae]

Re: Tohatsu 90 hp tldi all 3 tach lights blink on

Well I bit the bullet and replaced the almost new battery with a 120 ah 1000cca and will take the boat for a ride today and see if that fixes the issue.

Fixed.......ran perfectly.

 

[rcl700]

Re: Tohatsu 90 hp tldi all 3 tach lights blink on

Wow !!

glad to hear it. I will have to keep an eye on my battery.

Did you have the old battery tested? or do you think it was just down to the cranking amps?

 

[jshoes52]

Re: Tohatsu 90 hp tldi all 3 tach lights blink on

Here's what happened to me a few years ago. I had the same symptoms as you...all three lights would flash and forced idle speed. Troubleshooting with the manual led me to a power shortage at the TPS. I bought a new battery and still had the intermittent problem. Then one day I went to start the boat at the ramp, and the self-test warning beep upon turning on the key just kind of chirped a little instead of making the usual robust beep. I put the boat back on trailer and went home.

After some searching, I found that I had water in my key switch. This caused the anemic beep, and I surmise it also caused the low voltage to the TPS error code. I have a center console boat and the key switch is (used to be) open to the weather. My dealer gave me a new switch and it was fine.

Then in a separate event a couple years ago, first thing in the morning the motor would turn over very slowly as if the batteries were dead. I would have to switch to "both" on the battery switch to get started. No low voltage warnings appeared though. I remedied that by running new, unspliced battery cables from the batteries under the center console to the motor. When the motor was originally installed by the dealer, he had spliced about 15' of battery cable to the 6' factory-supplied battery leads to reach the batteries under the console.

Also interesting is that one of my batteries is an original from 2003 when I finished my boat and launched her. I believe it's about a 900 cca group 24 from Hamilton Marine. The motor will start and run on that battery alone even when there's frost all over the boat. I bring the batteries into the shop over the winter and alternate them on a battery maintainer over the winter.

Despite the electrical glitches which were no fault of the motor anyways, I have to say this motor has been flawless in every way. In seven seasons and almost 300 hours, I don't think it has ever even stalled on me.

 

[Danjae]

Re: Tohatsu 90 hp tldi all 3 tach lights blink on

Here's what happened to me a few years ago. I had the same symptoms as you...all three lights would flash and forced idle speed. Troubleshooting with the manual led me to a power shortage at the TPS. I bought a new battery and still had the intermittent problem. Then one day I went to start the boat at the ramp, and the self-test warning beep upon turning on the key just kind of chirped a little instead of making the usual robust beep. I put the boat back on trailer and went home.

After some searching, I found that I had water in my key switch. This caused the anemic beep, and I surmise it also caused the low voltage to the TPS error code. I have a center console boat and the key switch is (used to be) open to the weather. My dealer gave me a new switch and it was fine.

Then in a separate event a couple years ago, first thing in the morning the motor would turn over very slowly as if the batteries were dead. I would have to switch to "both" on the battery switch to get started. No low voltage warnings appeared though. I remedied that by running new, unspliced battery cables from the batteries under the center console to the motor. When the motor was originally installed by the dealer, he had spliced about 15' of battery cable to the 6' factory-supplied battery leads to reach the batteries under the console.

Also interesting is that one of my batteries is an original from 2003 when I finished my boat and launched her. I believe it's about a 900 cca group 24 from Hamilton Marine. The motor will start and run on that battery alone even when there's frost all over the boat. I bring the batteries into the shop over the winter and alternate them on a battery maintainer over the winter.

Despite the electrical glitches which were no fault of the motor anyways, I have to say this motor has been flawless in every way. In seven seasons and almost 300 hours, I don't think it has ever even stalled on me.

Shoes,

I use my boat two times a week on average, year round. I bought the engine new in 2004 and in those years have had 4 problems. Once it was loose battery connections...once it was a clogged fuel fitting that connects on the engine due to ethanol eating the inside of the priming ball and this time what turns out to be yet another battery issue. The only actual engine problem I have had was a bad o2 injector replaced under warranty. The engine starts every time just like a car, turn the key and it starts up no stalling. To say I am happy with this engine is a gross understatement. Was out Friday trolling for grouper and the engine was flawless. Not sure why they make the engine so particular about batteries though.

 

[Danjae]

Re: Tohatsu 90 hp tldi all 3 tach lights blink on

Wow !!

glad to hear it. I will have to keep an eye on my battery.

Did you have the old battery tested? or do you think it was just down to the cranking amps?

I did not have it tested......I bought a new battery a couple months ago and two weeks later it died......replaced it and this one lasted 2 months. I should know better than to buy Walmart batteries. It is my fault as Tohatsu clearly states 850 CCA and that batt was 720.