help with my 1994 Yamaha 150Hp TXRS

[BayouNola]

Hello I just bought a new boat (used but new to me) and having a few issues. When im in ideal the motor runs fine until I go over 4800rpm. when at that rpm the motor surges as if it needs gas or not firing on ALL 6. As I attempt to go faster the alarm goes off. when I pull back the alarm goes off. tryand go faster for 15 min then the alarm goes off. water pump is coming out like a race horse or fire hose. ive change the fuel line and all gas stuff. I Changed the both thermostats plugs and still had issue. I was told by a Yamaha dealer it was an electrical issue possibly the CDI? Im not sure what it is. im going to change the water pump to see if that's it. could it be the CDI??? help I just want to go fish. Help Thanks

[rodbolt17]

what tachometer is it rigged with ?

[BayouNola]

yamaha tach

the boat came with 2 Yamaha tach. Yamaha G310-1 RPM Tach and the Yamaha G320-1 Speed, Fuel,. Could my problem be electrical? As I stated I changed ever fuel filters that the motor has including the spark plugs. Even though the water port is coming out cool and strong. Im going to change the water pump (Impella). Any advice would help and be very grateful. Someone said it could be the CDI.Is that possible would that set the alarm off if its not firing on all 6? Thanks

[rodbolt17]

when the alarm goes off, what visual inditcates are on the tach?

[TownsendsFJR1300]

Was there much / any salt corrosion inside the head when you pulled thermostats?

Do you know if the boat / engine was used mostly in salt or fresh water?

[BayouNola]

If you are looking at the TACH the first symbol which think is the temp goes off. I may be wrong but it looks like the temp symbol. As far as how the thermostat looked. they had a little white crust on them. The boat has always been in the waters in the New Orleans area. With the Mississippi River flowing into the gulf all the water ways are half salt and fresh water. so not as much salt water here like waters in Florida. Hope this can help you answer my question. what could cause the problem Im having????

[TownsendsFJR1300]

We have brackish water (more salt than fresh) and salt water once you make it to the gulf. My neighbors V6 200 acted the same as yours. The only difference was the overheat alarm would go off, RPM's cut way down. You'd have to turn off, then turn on again to get the buzzer to re-set.

As long as you kept it under a certain RPM it was fine.

We found one thermostat stuck partially stuck open, there was a decent amount of corrosion in the thermostat area (he didn't flush it often). We replaced the water pump, pissed like a race horse, SAME PROBLEM, maybe picked up a 100RPM.

Ended up pulling both heads, there was sooo much salt build up in the water jackets, I don't know how it ran that good. The lower two cylinders were about 90-95% blocked, literally. One of the sensors is right there. As the engine got hot, with little to no water flow to the head, the overheat kicked in and shut the engine down.

After much picking, scraping etc, we got everything petty damn clean. Put her back together, ran like a raped ape!

The marina, to do that job was about $700. With gaskets, several (maybe more than several) hours it was about $150 in parts...

[BayouNola]

still need help

Could my problem be an oil issue. I described what type of Yamaha Tach I have. When the alarm goes off the tach illuminates red. Its the symbol to the bottom left if you look at the tach. Should I try changing the oil filter. Where is the oil filter located? Im changing the water pump today but something tells me its something else. Ive found other links online with very simular problems. Same issues with the 150Hp V6. As stated my motor is a 1994 TXRS. THANKS

[amahaork]

could be oil filter under sub-tank

[99yam40]

Could my problem be an oil issue. I described what type of Yamaha Tach I have. When the alarm goes off the tach illuminates red. Its the symbol to the bottom left if you look at the tach. Should I try changing the oil filter. Where is the oil filter located? Im changing the water pump today but something tells me its something else. Ive found other links online with very simular problems. Same issues with the 150Hp V6. As stated my motor is a 1994 TXRS. THANKS

Look up an owners manual for your motor or one close to yours, it will have a description of the tach and the warning indicators.
My thoughts are it is an overheat not oil indicator coming on, but should be easy to look up and verify

[rodbolt17]

and now we are getting somewhere.
like pulling teeth, or tooth depending on your location.

that left hand redlamp is low engine tank level.

your description indicates a clogged remote tank filter or a pinche oil line between the tanks.

the overheat icon is located in the speedometer.

its why rigging with factory Yamaha stuff is nice.

a quick oil system test on that V6.

drain the engine oil tank.
sometimes heat from a hair dryer or heat gun will aid in loosening the water trap.
PUSH the trap off DO NOT PULL.

replace the trap.

make sure the remote tank is 1/2 full.
turn on the key.
you should now have an audible alarm and all three lamps flashing.
the oil pump will turn on for 180 seconds.

the engine tank should fill and shut off the transfer within the 180 second time.

if it wont fill and the timer times out you have a restriction.

if the filter is clogged I recommend remote tank removal and cleaning when replacing that filter.

[BayouNola]

where is the oil filter located??

Mr. Rod thank you for your answer. I will try your suggestion. My question is where on the motor is the oil filter located. By the reservoir tank on the motor?? Please let me know im on my way now to my buddies auto shop to change the water pump. On my way im going to stop at the boat place and get a new oil filter to change. Im,( me) not sure where its located.. thanks always.

[boscoe99]

The oil filter is at the back of the boat mounted oil tank. Near the electric oil pump. Yamaha calls it a strainer.

Item 6 in the illustration at this linkhttp://www.boats.net/parts/search/Yamaha/Outboard/1994/150TXRS/OIL%20TANK/parts.html

[BayouNola]

thanks Bosc for the info. the cap has a hairline crack in it. would a hairline crack in the cap cause any of the issues I mentioned. Also today a buddy and I changed out the water pump. And when we dropped the lower unit and disconnected the small water hose. It was dry rotten but it was also caked solid with white stuff (salt). I guess the inside the motor (water jacket) is most likely the same????? Thanks for the response

[BayouNola]

Bosco Im just realizing I did not mention what cap Im speaking of. Its the cap to the main oil sending unit to the link you gave me. Is that a possible problem to my 1st original question????? Thanks