Tohatsu 50 TLDI running rough

[BobGlover]

I purchased a 50 hp Tohatsu TLDI last January, ran it through the break-in period last spring and recently started using it for winter fishing (my favorite season). Recently it began missing and running rough at both high & low speed. The dealer recommended that before I bring it in to change the plugs, gas (I don't use ethanol gas) and check the battery. He said it is common for these motors to foul the plugs after the first few hours. Does this sound correct? Seems to me the plugs should last longer than this--I don't have 10 hrs on the motor past the break-in period. A spare set of plugs came with the motor. Can I clean & reuse the old plugs for spares?
Thanks!

 

[Sea Rider]

Re: Tohatsu 50 TLDI running rough

Don't see why first plugs cannot be used again, TLDI engines should use less oil ratio than a standard 2 stroke engine during break in period. Before sending engine to dealer, clean plugs and test, probably that's all to it. Plugs do get fouled during break in period, but not to the extend as to make engine miss at low and high speeds, have not experienced so so far, and that's me.

Happy Boating

 

[pvanv]

Re: Tohatsu 50 TLDI running rough

Bob.

Your dealer should look at it under warranty. As noted, first check plugs, and verify that you are using DFI-rated oil. If it's a factory defect, the service will be free. If it's due to conditions beyond the manufacturer's control, i.e. bad gas or poor oil, the costs will be paid by the owner. Depending on the condition of the plugs, you might be able to clean and re-gap them, if they have a little fouling. But keep in mind that the ceramic insulator is slightly porous, and if conductive oil carbon is soaked into them, they will never work as well as new.

TLDI motors are not "shade tree mechanic" friendly. If there is a serious issue, the technician needs to review the diagnostics, and must use the FSM to guide the repairs.

 

[BobGlover]

Re: Tohatsu 50 TLDI running rough

Paul, Thanks a lot for the information! I finally read the owners manual and it recommends the plugs be changed or cleaned after the first month or 20 hours. I removed them and they look really bad. I replaced them with the set supplied in my owners kit and will change the gas also. Hope to try it out right after Christmas. One other thing; I checked the voltage on the starting battery and it was 12.51 volts. Is this an adequate charge for the 850 cca battery? I understand these motors require a big, fully charged battery.

 

[pvanv]

Re: Tohatsu 50 TLDI running rough

Bob,

That battery seems to show low voltage. I would expect about 13.5v... Or at least over 13... Use a known-accurate voltmeter. Check the specific gravity with a hydrometer, if you have removable caps on the battery. If in doubt at all, get a better battery.

Tohatsu wants you to use a battery of 1000 cranking amps. If you have room for a group-31, that's pretty easy to do, especially if you opt for an AGM battery. If you only have the space for a group-27, get one with the highest cranking amps you can get. If you are above 32F, the MCA number should be at least 1000, but if you are colder than that, look for a 1000 CCA battery... relatively rare in a flooded battery, even in the group-31 size.

Arkansas is warmer than Alaska, but if it's too cold out, your marginal battery may not have the proper reserves to allow the ECU to initialize correctly while the starter is cranking. In general, Lead-acid batteries of all types cannot deliver as high an amperage when they are really cold -- they work better when warm. If/When the ECU doesn't initialize correctly, all bets are off, because if the ECU does not initialize correctly, really weird operation can occur.

 

[BobGlover]

Re: Tohatsu 50 TLDI running rough

Bob,

That battery seems to show low voltage. I would expect about 13.5v... Or at least over 13... Use a known-accurate voltmeter. Check the specific gravity with a hydrometer, if you have removable caps on the battery. If in doubt at all, get a better battery.

Tohatsu wants you to use a battery of 1000 cranking amps. If you have room for a group-31, that's pretty easy to do, especially if you opt for an AGM battery. If you only have the space for a group-27, get one with the highest cranking amps you can get. If you are above 32F, the MCA number should be at least 1000, but of you are colder than that, look for a 1000 CCA battery... relatively rare in a flooded battery, even in the group-31 size.

Arkansas is warmer than Alaska, but if it's too cold out, your marginal battery may not have the proper reserves to allow the ECU to initialize correctly while the starter is cranking. In general, Lead-acid batteries of all types cannot deliver as high an amperage when they are really cold -- they work better when warm. If/When the ECU doesn't initialize correctly, all bets are off, because if the ECU does not initialize correctly, really weird operation can occur.

Paul, Thanks a lot for the information! I bought the battery last January from the same dealer that sold me the motor. The problem may be that the battery hasn't been used much and the motor hasn't been run enough to fully charge it. I've changed the plugs, will get new non-ethanol gas & will put the battery on a charger so it's fully charged. Hope to try it out soon after Christmas. In your opinion, are these pretty reliable motors? Thanks again, and Merry Christmas!
Bob Glover

 

[pvanv]

Re: Tohatsu 50 TLDI running rough

Bob,

Check the fluid level of the battery, charge it, and check the specific gravity. If it's in specs, you should be OK, as long as the temps don't drop too low -- that would lower the CA of any battery.

We have found the TLDI to be as good as any, and better than most, DFI motors. They have lower emissions than even a carbed 4-stroke of similar output, and can tolerate a lot of abuse. They are based on the 2-stroke blocks of old, which were the most reliable of any ever.

 

[ram95]

Re: Tohatsu 50 TLDI running rough

I purchased a 50 hp Tohatsu TLDI last January, ran it through the break-in period last spring and recently started using it for winter fishing (my favorite season). Recently it began missing and running rough at both high & low speed. The dealer recommended that before I bring it in to change the plugs, gas (I don't use ethanol gas) and check the battery. He said it is common for these motors to foul the plugs after the first few hours. Does this sound correct? Seems to me the plugs should last longer than this--I don't have 10 hrs on the motor past the break-in period. A spare set of plugs came with the motor. Can I clean & reuse the old plugs for spares?
Thanks!

How about the fuel you are using. Are you positive there is NO WATER in the fuel tank? This sounds like a water problem. Step ONE is you need to eliminate fuel as the problem.

Get a clean 5 gallon pail, dump all the fuel into the pail, dry out the fuel tank by tipping it so that all residual fuel flows into one corner of the tank and then absorb it with a paper towel. Once the fuel sets for about 20 minutes you can pour the fuel back into your tank. Watch closely to see if there is a "tongue' of water present as you are pouring the fuel. My guess is you'll find water.

 

[BobGlover]

Re: Tohatsu 50 TLDI running rough

Well, it finally warmed up enough for me to try out the motor. I changed the fuel, plugs, and recharged the battery. The motor ran fine. Hope this does the trick--I'll try it out more when the weather warms. Two questions; can you burn off the carbon on the old plugs with a propane torch? I'd like to save them for spares in case the other ones foul while I'm on the water. Also, what is the BEST oil to burn in these motors? My dealer recommended Yamalube. Is this the best?

 

[tohatsu9.9guy]

Re: Tohatsu 50 TLDI running rough

Carbon is formed due to burning, so more burning probably won't do much to rid the plugs of it. Try cleaning them up with some fine sandpaper then rinsing them with carb cleaner or similar solvent to remove any possible grit that you don't want in your engine.

 

[pvanv]

Re: Tohatsu 50 TLDI running rough

Once the insulators have been saturated with oil carbon, the plugs are shot. Carbon conducts electricity, so it reduces the insulating qualities of the ceramic insulator. Any DFI-rated oil will be OK. Of course, I would recommend the top brands, such as the Tohatsu labeled products.

 

[Sea Rider]

Re: Tohatsu 50 TLDI running rough

Buy a portable sand blaster for plugs at auto shop, will leave all plugs immaculate clean as you want them.

Happy Boating

 

[pvanv]

Re: Tohatsu 50 TLDI running rough

No engine manufacturer ever recommends sandblasting plugs. That process went out of style with the 1950's. The residual grit is not good for the motors, and the erosion of the insulators isn't good, either.

 

[TOHATSU GURU]

Re: Tohatsu 50 TLDI running rough

I think we stopped trying to clean plugs somewhere in the mid 70's as the cost of the labor exceeded any potential cost savings by reusing the same plugs...I can see that if you were in a mud hut environment cleaning a sparkplug would be a viable solution. I'm not sure what ever happened to that little blaster/bag, but I wish I still had it

 

[ram95]

Re: Tohatsu 50 TLDI running rough

Regarding 2 stroke oil.. Yamalube is certainly good... but the oil sold by Tohatsu is equally good if not better. I race the M50D2 carbureted version of this engine. Tohatsu has a new advanced synthetic oil #332923050. Tell your dealer the Mad Russian sent you.

 

[Sea Rider]

Re: Tohatsu 50 TLDI running rough

If you're using extreme high pressure on a sand blaster, probably will erode the insulator, new portable sand blasters are connnected to air pumps which can be air pressure adjusted to be gentle with overall blast. Plugs are not eternal, usually replace mines at max 100 worked hours and a middle clean & regap every 50 hours. Add higher octane gasoline and best 2 strokes oil available and will have engine running top all day long with minimum carbon deposits on combustion chamber and mint cond plug tips.

Happy Boating

 

[BobGlover]

Re: Tohatsu 50 TLDI running rough

Thanks guys...I think I could buy 3 new plugs at $18 ea for the price of a sandblaster. The new plugs should last me at least 100 hrs. If they don't, I've got a 6 yr warranty & back to the dealer's shop it goes!

 

[pvanv]

Re: Tohatsu 50 TLDI running rough

Thanks guys...I think I could buy 3 new plugs at $18 ea for the price of a sandblaster. The new plugs should last me at least 100 hrs. If they don't, I've got a 6 yr warranty & back to the dealer's shop it goes!

The plugs will last the longest if you use the best DFI oil. We like the Tohatsu-labelled fully-synthetic oil. It's not cheap, but it leaves almost no residue, saving you $$ by leaving less carbon. You can get it from any Tohatsu/Nissan dealer:

• Exceeds the NMMA TCW3 oil rating standard
• 100% Synthetic Oil with custom high-performance additive technology
• Far easier cold starting than competitive oils
• Ultimate lubricity & wear protection
• Engine cleanliness – reduced carbon and deposits
• Increased anti-wear additives for extended engine life
• Low smoke
• Outstanding corrosion & rust protection
• Tohatsu engineering tested and approved

332923050M TOHATSU COMP ADVAN SYNTH TLDI OIL (4-GALLONS) $155.50

 

[stancel]

Re: Tohatsu 50 TLDI running rough

Mine did the exact same thing. Turns out the battery was probably the culprit. Dealer I bought it from sold me a cheapo battery.

 

[TOHATSU GURU]

Re: Tohatsu 50 TLDI running rough

Since Tohatsu pays shop labor rate I think I would discount the dealer's rationale completely. Back to my original statement from your old post.

"ANYTHING"

It has to go to a dealer that is willing to spend the time to find the problem. Sometimes that problem is a set of plugs, sometimes an injector, sometimes the wrong oil and sometimes the problem just goes away all on it's own. Often taking the engine to a different dealer can result in a quick fix. Even the best of techs will sometimes look at something and not see the glaringly obvious. A new set of eyes can do wonders sometimes. Also, I don't know John Adams, he must be new.