2007 Tohatsu MD50 Outboard ? - Hard to start, and when she fires very high idle.

I just bought a low hour 2007 MD50 for my inflatable. during my 2nd run around the lake while canal cruising she just stalled.
I noticed all three light blinking and she was hard to start, but when I twisted the throttle wide open she did fire.. I thought it might be the plugs loaded up so I limped out toward my house with the intention of "clearing the engine out with a wide open throttle pass".. But the motor seemed like it was in a guardian mode and would not allow much more than idle speed.

So when I got home I pulled the boat out, hooked up some ear-muff and started her.. once again very hard to start and once started she revved very high and would not come down. (Turned off)

- I replaced the fuel with fresh gas (same)
- I checked the fuel lines for damage, collapsing or a vapor lock (still the same)
- I pulled the fuel filter, cleaned and replaced (same)
- I check for air in the fuel system from the Schroeder (sp?) valve (same)

I also checked the battery connection thinking that might mess with the TPS and found i was able to move the negative cable with a stiff push.. so I cleaned it and re-attached. (The lights are off now, but the same high idle with a difficulty to start problem is still with me).
also notice if I disconnect the TPS while she’s running the idle drops to normal, but I'm unable to rev the engine and it feels like it’s in a guardian mode again.

The owner’s manual does not have much information and I most likely going to order a service manual today, but would anyone have a "check this" list I can do before the manual arrives?

Thanks

After work yesterday I came how and replaced the spark plugs, she fired right up with no throttle and idled low. Than after a couple seconds she started ramping up the idle till she was back to its hi idle. I turnedthe motor off after a moment and when I went to restart her it needed a full throttle twist to start.

This leads me to believe I have a stuck fuel injector... than the heavy rain came, so I was finished

Rick,

The TLDI series isn't very "shade tree mechanic" friendly. You really need the Factory service manual to get anywhere. Then put the motor in diag mode and read the codes to see what errors and conditions it tells you. The battery MUST be very good; Ideally 1000 cca. Otherwise the ECU may not initialize correctly. Many problems get resolved by resetting the TPS initial setting. There are schraeder valves on both the air and fuel rails, for checking pressures. Because the fuel runs through a vapor separator, there should never be any air in the fuel rail. Depending on your serial number, you may need air injectors replaced under a recall campaign.

I'm about as shade tree as you get... the nearest dealer is a hour plus drive. So before I load the boat up and run across town I figured I can check the easy stuff.

- the battery tested good, buts a couple years old so I'll swap it out with a new one and place this one in my totter-home.

I did reset the TPS and the 3 blinking warning lights are all off, but she still idles hi. If I was to guess I would say the 2k range.

Another post said the new upgraded injectors are blue.. I have black injectors, but blue electrial caps that snap on.. not sure if the cap is what someone was refereeing to.

I do have some outboard experience as I do all my own mantanice on my Mercury 2.5/280 engines on my Superstock cat... some times its quicker to buy the right tools and learn than wait for a service shop.

But my merc and this are two very different animals..

Understood. Get a Factory service manual (not an aftermarket doorstop). Then settle in for some reading.

Unlike an e-tec, the TLDI is relatively low pressure, and uses a puff of air to get good atomization. So you have both fuel injectors and air injectors.
The AIR injectors are probably a pink color, and the deciding factor is the mfg number on the injector. Find the serial number, and the exact model number of the motor. If you need new injectors, they should be no or low cost to you.

Many TLDI issues are resolved by fixing wiring connections, so check over all plugs and lugs, especially grounds. Also make sure you have a BIG battery, and that it is well-charged.

Understood,..

I just double checked the injectors, they are a dark blue not black.. so I guess they are updated.

At this time I'm leaning towards dirty injectors as the engine starts right up and idles perfect after she's sat overnight. But once the motor has run a moment she ramps up the rpm and when turned off needs full throttle to be restarted.. and flooded motors need more air to fire.

I'll run some seafoam through the system and replace the battery tonight if time allows.. also call the dealer and see about making an appointment to try and limit down time.

Thanks

The air injectors are neither blue nor black.
Everything depends on exact model/serial of the motor, and mfg number on the air injectors, which are only accessible after removing the injector rail from the head.

A thermally-failing TPS or other sensor could also cause your issues.

Running Seafoam is like waving a magic wand. I have little faith in either. OTOH, it probably won't hurt.

I'm not sure of the air injectors colors, I was not looking at those really close this morning. The Fuel injector colors are a dark almost navy blue with a black electrical connection on top.

With the ethanol in the fuel I'm a big fan or running SeaFoam through a motor before storage and maybe once during the season..

and you are correct about the temp. If the engine temps reads cold it will dump fuel to richen her up causing a higher idle. with that being said I have never seen a computer dump this much fuel to cause the engine to rev this hi. with that said, I'm not saying it cant happen.. nothing is impossible just because its unlikely

Just called the nearest dealer, they are not trained to repair the TLDI engines.. So I called to the next nearest dealer, they are 30 min further.. I'm waiting on a call back, hopefully they work on them. If not I'll have to consider buying a engine scanner (if that's something that can be bought) or selling the motor for something with a little more local dealer support.

Thanks for your help

Not to worry. The only issue is that your nearest dealer has not been to Tohatsu school in Dallas. They can still repair them (if you trust them), but they can't do warranty work... and the warranty is long over on that motor. They CAN call Tohatsu America, and get good factory support.

The TLDI does its own diags, so you do not need a "scanner", though having some good tools and instruments helps a lot. Once you have the Factory service manual, much will become clearer.

As for the temp., I was suggesting that you could have a sensor (such as the TPS) that is failing when it heats up.

As for ethanol, in an EFI motor, the real issue is corrosion. However, all regular pump gas in the US today is "dirtier" than it was 20 or 30 years ago. The "premium" blends sometimes have more detergents, etc., so may be better. Also, you can often find ethanol-free gas if you check the http://www.pure-gas.org website. Best way around ethanol issues is to always run fresh (under 30 days) gas, and drain the vapor separator (looks kind of like a carburetor) when storing. Remember that EFI motors have both high and low pressure fuel pumps, and fuel filters. Not knowing the service history of your motor, while servicing, you might want to go through those as well, to rule out corrosion issues. Also, be 100% sure that you are running oil that is made for DFI engines, not just TC-W3.

If you need to get Factory support for a dealer, so they can help you with service, (or locate a dealer), you can always call Tohatsu America directly, at 214 420 6440 and they will be happy to help.

Great info, Thanks again

Port Clinton Oh seems to be my nearest dealer willing (or able) to work on this.. I'm located 45 min North of Detroit MI

The plus side is a shop emailed me a pdf. of the troubleshooting section of a service manual. .. not much additional information so far, but with every part I rule out its one step closer.

Ok.. I cleaned the tank, new fuel with some seafoam.

She fired up, ran high and slowly ramped down.. than stalled. I fired her up, she idled hi, low, hi, low.. all over.

She now starts without full throttle, sometimes...

And to top off the night the dealer I called said they cannot work on my motor..

* Last night (after working on the boat) was typed with my phone so I did not get into specifics as I hate typing on my phone..

So
- I bought a new 1000CCA battery made for these TLDI systems. Not a DEEP CYCLE MARINE *

- I installed the new battery

- Checked the fuel tank. I dumped the old fuel into my mower and noticed a little black dirt..so I cleaned the tank. While cleaning the tank I noticed a "hole" in the fuel pick up line. So I unscrewed the pick up and found the line was hard, brittle and broken. I also noticed the hole was toward the top so the fuel sucked up would also have "air". Fixed line, reinstalled with fresh fuel and SeaFoam.

- Re set TPS

- Boat fired right up and after lets say 5/10 sec. the idle slowly started going back up.. maybe 2000 rpm. It has not tach so I'm guessing..

- I allowed her to idle for maybe 5 min and noticed the idle would slowly drop, than ramp back up.. than it slowly dropped and stayed low and stalled.

- I fired her up (no throttle needed) and she was idling ok, but started going back up, than down, than up... very inconsistent. at this point it was starting to get dark and I dont want to be that "neighbor" so I called it a night.

- The one dealer that said they could work on them called me back and said they dont have the tools (?), this is the 2nd one.. is this engine designed by NASA or something??

Regarding the battery... [flooded] Marine batteries come in two basic kinds: Starting and Deep Cycle. Starting batteries have a lot of thin plates, and can deliver a lot of amps for short busts of time. Deep Cycle batteries have fewer (but thicker) plates, and can tolerate a deeper discharge, but are unable to deliver a huge rush of amps for starting. If the battery is not going to be discharged below 75% (an electric trolling motor might take it down to 25% or less), the Starting variety is fine.

If you feel that you may have sucked up some dirt, you should check the low-pressure fuel filter, and possibly replace the inner element. If only a little air got in from your defective fuel pickup, that should disappear at the vapor separator, unless it's a lot of air. While at the vapor separator, it never hurts to drain it (especially if the motor was stored without draining), as there could be fuel sludge in the bowl; then re-prime the system with the primer bulb.

The design of the TLDI is actually pretty straightforward, but it's best to have a mechanic who understands the specifics of that system. Your issue could be as simple as a poor ground (or a corroded wiring connection), or it could be more involved. The technician need to be able to measure air and fuel pressures (on the order of 100 psi), and needs to have tools similar to what is used on any modern DFI motor. It's best if the technician has attended school at Tohatsu America.

I show 6 dealers within 100 miles of your general area. You may want to call Tohatsu America to ask whether your motor may be affected by the air injector replacement campaign. They should also be able to refer you to a dealer.

I would guess that all Tohatsu dealers would service all Tohatsu outboards, that's not so....at least in my area. Did not have a change to clean the filters and fuel system this weekend as I was busy with big boat work. Maybe during the week.. if its not the fuel system i'll schedule a road trip to a dealer that will work on my little outboard.

But she does run better, and she runs.. so thats one step in the correct direction.

All Tohatsu dealers can service all Tohatsu motors. If the shop doesn't have a Certified TLDI technician, they are not allowed to SELL TLDI motors. It would be good if Tohatsu America was made aware of which dealers are not helping you.

I'll do a quick fallow up - I cleaned the filter, lines and tank. than re-fired her with a couple gallons of fresh fuel and seafoam. I just let her idle in the water.. at first the idle was high, but slowly dropped to normal.

After maybe 30 min I took her out canal cruising at a mellow pace, Just fast enough to add a little load to the engine. I slowed down, shifted to neutral and with no load she reved up slightly but idled back down.

after a 20 min ride around the house she idles most the time normal with a occasional high idle tossed in. I still think shes dumping fuel, just not as much. If it wont clear up after a full tank I'll pull the injectors and have them cleaned.

but so far so good.


thanks for the help.

- Pvanv - I was told buy two of the dealers that they are not equipped to service the "large" outboards.. what ever that means. I figured if you sell them, you sell them all.

They may not be equipped with a larger test tank, etc.