yamaha outboard question

[the lackster]

Looking for help here...again. I have a 1993 yamaha tlrr 70 HP carbureted 2 stroke "pre mix" yamaha with some issues. Could the reed valves be the cause of the boat not having power "bogging down as soon as i give it throttle"? I ask because I pulled the air box off and the bottom two chambers of the air box have gas oil mix in them.

Could a bad reed valve be allowing air back through the carbs causing this. I have just about replaced everything to do with fuel on the motor and still no luck. New lines, spark plugs, primer, tank drained/cleaned, carbs cleaned/ parts replaced, even replaced a whole carb that had a broken jet from previous owner. Compression is 110 on all 3 cylinders and timing is where it needs to be according to the mechanic that works on my boat. It's back in the shop again but I'm trying to learn as much as I can about the motor. Any help is greatly appreciated.

 

[teearr]

Looking for help here...again. I have a 1993 yamaha tlrr 70 HP carbureted 2 stroke "pre mix" yamaha with some issues. Could the reed valves be the cause of the boat not having power "bogging down as soon as i give it throttle"? I ask because I pulled the air box off and the bottom two chambers of the air box have gas oil mix in them.

Could a bad reed valve be allowing air back through the carbs causing this. I have just about replaced everything to do with fuel on the motor and still no luck. New lines, spark plugs, primer, tank drained/cleaned, carbs cleaned/ parts replaced, even replaced a whole carb that had a broken jet from previous owner. Compression is 110 on all 3 cylinders and timing is where it needs to be according to the mechanic that works on my boat. It's back in the shop again but I'm trying to learn as much as I can about the motor. Any help is greatly appreciated.

Maybe you need another mechanic? Not being critical or judgemental but a good mechanic should be able to answer your questions. Good luck.

 

[the lackster]

Maybe you need another mechanic? Not being critical or judgemental but a good mechanic should be able to answer your questions. Good luck.

His initial guess is reed valves but he hasn't got inside the intake yet to confirm. Joys of my boat tearing up in the spring time and being in line with all the other boats trying to get on the water. There is a wealth of knowledge on here and no two people explain something the same thing the same way. Never hurts to ask.

 

[teearr]

His initial guess is reed valves but he hasn't got inside the intake yet to confirm. Joys of my boat tearing up in the spring time and being in line with all the other boats trying to get on the water. There is a wealth of knowledge on here and no two people explain something the same thing the same way. Never hurts to ask.

While you're waiting your turn for service you might want to try "mechanic in a bottle". Don't laugh, but I had a Stihl chainsaw that had sat with ethanol gas in it for almost 3 years and was just "gummed" up. I squirted some MIAB in the carb. and let it sit for an hour. Then I emptied out the gas/oil tank and refilled it with an ethanol free gas/oil mix and it started on the 3rd. pull. Ran a bit rough for awhile but then it smoothed out and didn't choke when I opened the throttle.

Of course YMMV so you might want to check my suggestion out before you try it Good luck.

 

[LARGO9]

Sounds more like a power pack coil, they will let it run but break down when you give it more throttle.
If you have that much fuel in the air box look at you reed screws, they should be pointed, over time they will round off and cause the motor to run rich letting to much fuel in the carb, that is where your fuel is coming from.

 

[the lackster]

Sounds more like a power pack coil, they will let it run but break down when you give it more throttle.
If you have that much fuel in the air box look at you reed screws, they should be pointed, over time they will round off and cause the motor to run rich letting to much fuel in the carb, that is where your fuel is coming from.

Awesome, thank you!

 

[the lackster]

While you're waiting your turn for service you might want to try "mechanic in a bottle". Don't laugh, but I had a Stihl chainsaw that had sat with ethanol gas in it for almost 3 years and was just "gummed" up. I squirted some MIAB in the carb. and let it sit for an hour. Then I emptied out the gas/oil tank and refilled it with an ethanol free gas/oil mix and it started on the 3rd. pull. Ran a bit rough for awhile but then it smoothed out and didn't choke when I opened the throttle.

Of course YMMV so you might want to check my suggestion out before you try it Good luck.

It's sitting at the marine shop. He is supposed to take the intake off and get a look at the reed valves to see if thats the issue. It's about to drive me crazy being down this time of year!!

 

[teearr]

It's sitting at the marine shop. He is supposed to take the intake off and get a look at the reed valves to see if thats the issue. It's about to drive me crazy being down this time of year!!

Know what you mean - love my wife, but since I've been retired I seek out a quiet place to relax from time to time LOL. The middle of a lake is ideal (not suggesting your motives are the same as mine though ). Good luck.