2004 Tohatsu 30 hp 4-Stroke Problem

[ssanders14]

So on Saturday I had a tournament and our spot was about 10 miles from the launch site. We run wot for about 9 miles and the motor starts acting like it is getting caught in some hydrilla or weeds so I start bring the throttle back and the engine has stalled. When I try to start it it won't even turn over. I check the prop and there isn't anything on the prop and no damage to the prop. I thought the battery was dead. We fish for about 10 minutes and I try to start the motor again and barely turns over like the battery is dead. Wait about 45minutes and try to start the motor again and it starts but sounds really bad. So I shut it down. Start it a little later and run it on a low idle for about 5 minutes and it dies. I shut it down for the rest of the day and get a tow back to the ramp. When I get it home I put it on the muffs and it starts fine then about a minutes later it dies and the prop is turning a little in neutral. With the motor off it seems a little harder than it used to be to turn in neutral. When I get the motor in Forward and turn the prop it turns about a 1/4 turn then I feel some tension and then it clicks and turns about another 1/4 turn then clicks again. When in reverse it doesn't do this. Are my LU gears all messed up.

If this is difficult to understand let me know if you need me to clarify anything.

 

[pvanv]

Re: 2004 Tohatsu 30 hp 4-Stroke Problem

You probably have an overfilled crankcase. Check the oil level. If even a tad high, drain and change the oil. Do not overfill even a drop. Do not run synthetic oil.

The LU will ratchet in forward, so that's normal.

 

[ssanders14]

Re: 2004 Tohatsu 30 hp 4-Stroke Problem

I will change the LU oil as soon as I get a chance. I know now that some water got into the LU because yesterday when I checked it, it was a gray color. I think it is leaking from inside the prop. When I checked the prop the prop nut was so loose I was able to remove the nut by hand. What is the correct torque on the prop nut for my engine. I'm not sure of the serial number right now but I know it is a 2004 MSF30A with a 9.9 x 11 prop. Do I need a new prop if it is leaking from the prop or what do I need to fix that.

I didn't think it was normal for the prop to rachet when in gear with the engine off.

 

[TOHATSU GURU]

Re: 2004 Tohatsu 30 hp 4-Stroke Problem

Your best bet is to take it into a dealer to determine what, if anything is wrong. Your symptoms could be the result of a wide variety of causes and you would need to do a lot of troubleshooting to determine what the problem might be. A dealer can determine the problem in 30 minutes.

 

[pvanv]

Re: 2004 Tohatsu 30 hp 4-Stroke Problem

Gotta agree with Elvin. Especially since you have confused LU with crankcase, probably best to get to a dealer for an evaluation.

 

[ssanders14]

Re: 2004 Tohatsu 30 hp 4-Stroke Problem

Sorry if my reply was confusing. I need to change the LU oil too because it was gray and kind of milky when I checked it and the prop nut was way too loose. I will also change the engine oil before I try and run the boat again.

 

[pvanv]

Re: 2004 Tohatsu 30 hp 4-Stroke Problem

OK, here's my read so far:

You have a running issue, and you have a leak in the LU.

At 5 years of age, it would be prudent to drop the LU and at least inspect the impeller. Since the labor is the same, plan on replacing the impeller. Tohatsu has a WP kit, which includes impeller, bolts, and associated wear parts/gaskets -- best way to go if you need a new impeller. Also, water intrusion in the LU means a bad o-ring or seal. Typical points of leakage are the [often overlooked] shift rod o-rings, and the seals for the driveshaft and propshaft. While you have the LU apart, it would be a good idea to spend an extra couple of bucks and change all the LU seals and o-rings, including the big o-ring for the propshaft housing "spool". After all, the lion's share of this job is in labor, which you will have already invested. BTW, The prop gets torqued to zero lash, and then the cotter pin gets installed to keep it that way. If necessary, you can tighten the prop nut an additional 1/12 of a turn to get the cotter to line up in the castellated nut. These are spline-drive props, and they do not need to be torqued like the old tapered-shaft props.

As for the running problem, it could be almost anything. This needs to be diagnosed properly. First and easiest check is to verify the motor oil level and condition before you drain the oil. 4-strokes can "make oil" (there are a ton of threads on that topic on iboats), especially at low speeds, or if the crankcase is overfilled. If the oil level is high, and/or if it is contaminated with water and/or fuel, you have probably been making oil. If so, changing oil (do not run synthetic oil) may fix that problem. But, in the event that the oil is not overfilled/contaminated, there are a ton of other things to check.

If the motor will not even crank, the most common problem on the 30 is liquid lock from an overfilled crankcase, but, as I said, there are a lot of other things that could be causing the issue. You should pull the plugs to check condition, and look for possible oil in the cylinders (caused by a high oil level). But you may also have wiring or starter problems, etc.

Once you are able to crank properly, and have correct oil level, any running issues are likely ignition- or fuel-related. If you get into that situation, you will want to diagnose THAT problem.

If this gets beyond your skill level, a dealer will be the best bet. If you will be doing this on your own, a Factory service manual will be your friend, and a wise investment.

 

[ssanders14]

Re: 2004 Tohatsu 30 hp 4-Stroke Problem

What type of Oil do you recommend for the Engine and the Lower Unit. Also is it ok to use an oil filter from the Auto Parts Store?

 

[pvanv]

Re: 2004 Tohatsu 30 hp 4-Stroke Problem

Check your owner's manual (available at Tohatsu's website if you have misplaced yours) for lubricant requirements.

The crankcase can run 10w-30 or 10w-40, depending on ambient temperatures. It should be non-synthetic 4-stroke OB oil (not TCW-3, which is for blending into 2-stroke fuel). 4-stroke OB oil has more corrosion inhibitors than ordinary automobile oil. In Buffalo, where the mercury has yet to ever hit 100F, we use 10w-30 in our customer's units.

Synthetic oil will promote "making oil", so don't use it. And don't just dump the oil in, guessing how much is in there. If you overfill, even a drop, you are asking for problems. Half-way or a little more on the dipstick is a good fill. Remember that the filter holds about a cup of oil, and remember that it takes time for the oil to drain back down into the pan from the valve train after running. So after changing oil and filter, re-check the level on the dipstick after a warm up and cool down.

The LU can run any decent 90 weight gear oil. We typically use synthetic blend 75w/80w-90 lube for the LU. You can get some really exotic stuff for the LU, and some of our customers think that they prefer it. Won't hurt. The important point is to keep the lubes changed at regular intervals.

We do not use el-cheapo filters on these motors. No way to know what micron size the elements are, and impossible to be sure how well they flow. YMMV if you use a no-name filter, and the Factory will not be required to honor the warranty if a poor filter causes an engine failure.