Hello, I have a five year old Tohotsu 3.5 hp outboard. I noticed over the span of the last few months that the "tell tale" water flow seemed to get less and less. When I hauled my boat out two weeks ago the flow was nill. The problem seems to be up in the engine as the impeler seems to work just fine. Any idea how to increase the flow? There seems to be some congestion internally. Thanks! -tap
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Try a Pipe Cleaner
I had the same problem on my Johnson 6 HP several years ago. A guest on my boat told me to clean out the output jet, where the water exits the motor, with a pipe cleaner. I tried it and it immediately fixed the problem. I now keep a pipe cleaner attached to the handle of the motor and use it whenever the flow slows down. I recommend that you try this and don't use your motor until you find out where the clog is. If my suggestion doesn't help, you may have to take your motor apart and see why it isn't pumping the cooling water. The impeller could be damaged. Aldo
I had the same problem on my Johnson 6 HP several years ago. A guest on my boat told me to clean out the output jet, where the water exits the motor, with a pipe cleaner. I tried it and it immediately fixed the problem. I now keep a pipe cleaner attached to the handle of the motor and use it whenever the flow slows down. I recommend that you try this and don't use your motor until you find out where the clog is. If my suggestion doesn't help, you may have to take your motor apart and see why it isn't pumping the cooling water. The impeller could be damaged. Aldo
How long?
How long has it been since the impeller was changed? You may be missing some of the rubber fins which will look like the pump is working , but it is not efficient. The fins may be a part of the clog. Most pump impellers have a life expectancy of 5 years max on a well used motor. With good info from your dealer, this can be changed in under 2 hours at a minimal cost. I don't know tohotsu's so you may ask him if other gaskets are required. A gear lube change will fill out an afternoon. merry Christmas r.w.landau
How long has it been since the impeller was changed? You may be missing some of the rubber fins which will look like the pump is working , but it is not efficient. The fins may be a part of the clog. Most pump impellers have a life expectancy of 5 years max on a well used motor. With good info from your dealer, this can be changed in under 2 hours at a minimal cost. I don't know tohotsu's so you may ask him if other gaskets are required. A gear lube change will fill out an afternoon. merry Christmas r.w.landau
Yup! Often a pipecleaner will work!
I agree with Aldo....... often times just giving the outlet port a good couple of strokes with a pipe cleaner gets the gunk out of the top of the engine. I keep pipe cleaners in my boat toolbox. One word of caution....... do not operate the outboard for too long with no water flow. You will burn up that outboard due to no cooling. Happy Holidays!!
I agree with Aldo....... often times just giving the outlet port a good couple of strokes with a pipe cleaner gets the gunk out of the top of the engine. I keep pipe cleaners in my boat toolbox. One word of caution....... do not operate the outboard for too long with no water flow. You will burn up that outboard due to no cooling. Happy Holidays!!
Spiders?
If the pipe cleaner doesn't work, try blowing thru the exit hole and intake holes with high pressure air such as we fill tires. This cured a problem my Dad had with a 10 hp Johnson about 50 years ago. We think it had been clogged by a spider web. In a worse case, you may have corrosion and scale in the system, especially if it has been used lots in salt water. Dick
If the pipe cleaner doesn't work, try blowing thru the exit hole and intake holes with high pressure air such as we fill tires. This cured a problem my Dad had with a 10 hp Johnson about 50 years ago. We think it had been clogged by a spider web. In a worse case, you may have corrosion and scale in the system, especially if it has been used lots in salt water. Dick
R.W. Really?
R.W.: Really? I replaced my impeller in my Johnson 6 about 15 years ago. It didn't actually need it at that time. The problem was actually a clogged thermostat. I removed the thermostat, which looked like a miniature car thermostat and was about the diameter of a quarter. I have never replaced it, and probably won't since the water that I use the motor in is slightly salty by the end of the summer. I figured that it was just too vunerable to clogging and corrosion. Anyhow, is the life expectancy of an impeller really only 5 years? If so, I better get one to replace mine in the spring. Tim, you might want to try to determine if your motor has a thermostat in it That will stop the water flowing through the power head jacket. Aldo
R.W.: Really? I replaced my impeller in my Johnson 6 about 15 years ago. It didn't actually need it at that time. The problem was actually a clogged thermostat. I removed the thermostat, which looked like a miniature car thermostat and was about the diameter of a quarter. I have never replaced it, and probably won't since the water that I use the motor in is slightly salty by the end of the summer. I figured that it was just too vunerable to clogging and corrosion. Anyhow, is the life expectancy of an impeller really only 5 years? If so, I better get one to replace mine in the spring. Tim, you might want to try to determine if your motor has a thermostat in it That will stop the water flowing through the power head jacket. Aldo
That is what I was told.
I had a problem with my impeller and the dealer I bought it from said that impellers are typically good for an average of 5 years. I had a Ski boat with a larger inboard engine in my younger days. That motor had a seperate belt driven water pump. I would put in a new one at least once a year for the three years I owned it. Again, an impeller could last decades or a few days depending on the application. One grounding could pump sand or mud right though the water pump and destroy a new impeller. If you are not getting water flow, why mess around. Try some of the ideas posted here but if there is no result. Check the impeller. After the first time you tear into the lower unit it is less than a half hour job. The motor is too valuable to allow heat to damage it. Another small note, some motors need to be in or out of gear when removing and reinstalling the lower unit. When you buy the impeller, ask the dealer what is best. The impeller is probably a $10 to $25 item. It is handy to have one in the spare parts box. It saved me from loosing a weekend. Let us know what you find out. merry Christmas r.w.landau
I had a problem with my impeller and the dealer I bought it from said that impellers are typically good for an average of 5 years. I had a Ski boat with a larger inboard engine in my younger days. That motor had a seperate belt driven water pump. I would put in a new one at least once a year for the three years I owned it. Again, an impeller could last decades or a few days depending on the application. One grounding could pump sand or mud right though the water pump and destroy a new impeller. If you are not getting water flow, why mess around. Try some of the ideas posted here but if there is no result. Check the impeller. After the first time you tear into the lower unit it is less than a half hour job. The motor is too valuable to allow heat to damage it. Another small note, some motors need to be in or out of gear when removing and reinstalling the lower unit. When you buy the impeller, ask the dealer what is best. The impeller is probably a $10 to $25 item. It is handy to have one in the spare parts box. It saved me from loosing a weekend. Let us know what you find out. merry Christmas r.w.landau
impeller housing
I had a similar problem with my honda 7.5hp. my brother in law is a marine mechanic, so labor cost was nil. we did find that while the impeller itself was okay, the plastic housing around it on the inside had several large cracks in it. this affected the effectiveness of impeller. might want to check that too...
I had a similar problem with my honda 7.5hp. my brother in law is a marine mechanic, so labor cost was nil. we did find that while the impeller itself was okay, the plastic housing around it on the inside had several large cracks in it. this affected the effectiveness of impeller. might want to check that too...
Try this
Hi Tim, good advise from everyone so far, check the output hole as mentioned, mine has been plugged by spiders and mud daubers many times. Just as important is the intake, this usually has a fine wire screen over it and can get covered with marine growth or clogged with mud, sand, saeweed, ect. Also, don't rule out the impeller, even if it looks good, it could be bad. If you have ever run your motor out the water, even for 30 seconds, your impeller will be damaged. Age alone will not nessicarily be a factor, I have one motor that is 45 years old and still has the original impeller and it works just fine. Check the pump housing for cracks or leaks, a bad seal will cause it to lose pressure thus creating less flow. Some outboards have thermostats and by-pass valves that keep water circulating when the thermostat is closed. Thermostats can be checked by placing it in water that has been heated to the opening temperature (temp. should be stamped on it). A by-pass valve with a bad seal or that is stuck open will cause less output because the water will have more of a tendancy to recirculate that to exit thru the thermostat. I am not farmiliar with the Tohatsu, but I doubt it has a thermostat due to it's small H.P. Before you tear it down, the first thing I would try is flushing the system. All you need is a garden hose and a pair of "ear muffs", you can get them at Wal-Mart. Silt, sand, and the corrosive action of sea water can easily cause congestion, and flushing will most likely cure your problem. If you do have to tear it down, you can get a service manuel from the library to guide you thru the disassymbly. If all else fails, seek your dealers assistance. Best of luck, and happy holidays. Shawn
Hi Tim, good advise from everyone so far, check the output hole as mentioned, mine has been plugged by spiders and mud daubers many times. Just as important is the intake, this usually has a fine wire screen over it and can get covered with marine growth or clogged with mud, sand, saeweed, ect. Also, don't rule out the impeller, even if it looks good, it could be bad. If you have ever run your motor out the water, even for 30 seconds, your impeller will be damaged. Age alone will not nessicarily be a factor, I have one motor that is 45 years old and still has the original impeller and it works just fine. Check the pump housing for cracks or leaks, a bad seal will cause it to lose pressure thus creating less flow. Some outboards have thermostats and by-pass valves that keep water circulating when the thermostat is closed. Thermostats can be checked by placing it in water that has been heated to the opening temperature (temp. should be stamped on it). A by-pass valve with a bad seal or that is stuck open will cause less output because the water will have more of a tendancy to recirculate that to exit thru the thermostat. I am not farmiliar with the Tohatsu, but I doubt it has a thermostat due to it's small H.P. Before you tear it down, the first thing I would try is flushing the system. All you need is a garden hose and a pair of "ear muffs", you can get them at Wal-Mart. Silt, sand, and the corrosive action of sea water can easily cause congestion, and flushing will most likely cure your problem. If you do have to tear it down, you can get a service manuel from the library to guide you thru the disassymbly. If all else fails, seek your dealers assistance. Best of luck, and happy holidays. Shawn
earmuffs
HI Mike, the earmuffs go over the water intake ports on the sides of the lower unit. Some muffs are universal to fit most out boards, but you can them to fit a specific model from your dealer. Hope this helps. Shawn
HI Mike, the earmuffs go over the water intake ports on the sides of the lower unit. Some muffs are universal to fit most out boards, but you can them to fit a specific model from your dealer. Hope this helps. Shawn
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