50hp tohatsu

[native son]

my 50hp tohatsu doesn't seem to squirt very much water out the pee hole and at idle it is almost a trickel is this common
I have rebuilt the water pump and it didn't change
any information would be helpful

 

[TOHATSU GURU]

Re: 50hp tohatsu

It's not Abby Normal, but try running a small piece of wire up thru the pee and into the block while the engine is running. Salt/debris can clog them up. Also, you need to keep in mind that there is more to the cooling system than just the impeller. If you only replaced the impeller, then you need to pull it back apart and replace the liner and wear plate.

 

[native son]

Re: 50hp tohatsu

thank you as soon as I can make arrangements to get the rebuild kit I will try that I live in baja and getting parts is sometimes difficult

 

[deejaycee_2000]

Re: 50hp tohatsu

also pull the thermostat ..... check if all is working ....

 

[farnorth]

Re: 50hp tohatsu

Hello Native Son. I race a 50 Tohatsu in the Yukon 800 riverboat race in Alaska, and I've always had a problem with the Tohatsu's weak water pressure. I use a 50D (carburated) motor. I've tried the 50 TLDI water pump, cause it's bigger, with no increase in pressure. Sometimes on the river, we encounter a lot of drift and debris, and it stops the water pretty easily. This puts me at somewhat of a disadvantage to the Yamaha's, who always have tremendous water pressure. Any information on increasing the water pressure on the Tohatsu would be greatly appreciated.
I've: tried new water pump, impeller, chrome sleeve and plate. Removed thermostat. Tore engine down completely and made sure no jackets, outlets, or pickup tube was plugged.

 

[pvanv]

Re: 50hp tohatsu

Don't confuse pressure with volume.

It is the volume of water (with its ability to collect the BTU's of combustion) that cools the powerhead. The standard Tohatsu pump provides more than adequate volume for "normal" motors, even in tropical climes. Check the temperature of the discharge water stream -- it shouldn't be so hot you can't keep a finger in it. If it is boiling, you have a cooling system problem.

Now if you're running Nitrous or something, that's a completely different story.

 

[TOHATSU GURU]

Re: 50hp tohatsu

"Sometimes on the river, we encounter a lot of drift and debris, and it stops the water pretty easily."

The higher the pressure, the more likely you would be to attract and retain debris at the screen. The lower the pressure, the more likely you would be to have the water friction pull the debris away from the screen while underway. The screen is designed to keep out trash that could damage or clog the cooling system. If you want to bypass that protection then increase the size of the individual intake screen holes. Of course, your likely to fry the block so that would be an incredibly bad idea.

 

[farnorth]

Re: 50hp tohatsu

Thanks for the quick feedback. I'll go into a bit more detail. On my Yukon 800 50 Tohatsu, I have a nosecone on the lower unit for the low water pickup, with a screen I installed over the water pickup holes (on the nosecone). We run about 6000 rpm for about 6-7 hours to the halfway refueling stop.
What happens, is we encounter driftlogs in the river, and sometimes we have to cut throttle and skid over the log. The soft, waterlogged outer part of the log clogs the water system when it jams through the screen. Also, silt gets ingested into the water system when we occasionally skid over the sandbars while taking shortcuts. All this usually occurs from 55-70mph.
My Tohatsu's water system gets stopped pretty easily, whereas the Yamahas can run a lot of the finer stuff through the water system with no problem. I've rerouted the water outlet to the left side of the chassis, so I can reach back from the steering cockpit and feel the water with my hand while driving.
Any more advice and tips on this subject is tremendously appreciated. I can use all the help I can get trying to beat the Yamahas. (I run the only Tohatsu in the race.) Thanks again for the responses, folks. Tohatsu Guru, you sound like someone who would be able to help our race team tremendously.

 

[TOHATSU GURU]

Re: 50hp tohatsu

If I understand the problem correctly, you are shaving wood and muck into the pick up on the front/bottom of the cone. So, a modification to the low water pick up would be your only solution if there is one. Whose pick up are you using now?