Put my new/used (dealer claims less than 5 hours running time, and the motor looks brand new, but it's three years old and off warranty) Yamaha T9.9 electric start 4-stroke on the boat today, and had some problems with idling, stalling, and sputtery throttle response. The motor would run fine for a while, then it would start to sputter and slow down. Gunning the throttle would help most times, but it took several seconds for the motor to respond. Other times it would stall out, and could not immediately be restarted. I also had audible variations in RPM with the throttle in fixed position. I checked the plugs and they were black with soot. Soot on the plugs usually means too rich fuel mix or excessive idling, right? The dealer says the motor is still in break-in period, so I was careful to stay at half throttle or less. Since the motor has been sitting for a few years, I thought maybe some old gas had gummed up the carburetor, causing the erratic RPM's and the soot on the plugs. Is there a gas additive that will clean out gummy gas in the carb without taking it apart, and should I replace the plugs? Or am I barking up the wrong tree? PS: I plan to consult the dealer next week, but taking the motor back to the dealer will be highly impractical, since getting it onto the boat was a major PIA, and the marina is an hour away from the dealer. PPS: The reason the 3 year warranty is expired: the motor was briefly sold to someone else 3 yrs ago, who returned it to dealer after 2 outings because it was not a suitable trolling motor for a 225 HP equipped fishing boat; I bought it on consignment. It was a little more than half the price of a new one; a great deal, or so I thought.
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Still a good deal.
Tom: This can happen to any motor that sits. The first thing I would do is get some carb cleaner (Chemtool, STP, etc) and use it in a high concentration (1 can in 1-2 gal). Run some through the engine and let it sit and do it's job. If this does not work, I would also get some of the carb & choke cleaner and spray it into the air filter and see if this helps too. You may end up needing to change the plugs a couple of times as you proceed through this process. We just had the same thing happen to our Nissan 15! After messing with it for several weeks, it runs like a champ again.
Tom: This can happen to any motor that sits. The first thing I would do is get some carb cleaner (Chemtool, STP, etc) and use it in a high concentration (1 can in 1-2 gal). Run some through the engine and let it sit and do it's job. If this does not work, I would also get some of the carb & choke cleaner and spray it into the air filter and see if this helps too. You may end up needing to change the plugs a couple of times as you proceed through this process. We just had the same thing happen to our Nissan 15! After messing with it for several weeks, it runs like a champ again.
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Ray Bowles
Tom, You are now beyond the break in period .
A good portion of the soot on the plugs could be because of the way you have been running the motor at lower speeds. I would replace the plugs now so you can get a good plug reading in the future. Also run the engine much harder, it really need this at this point. Gas additives are not going to help at all in this situation. As for the roughness at idle and on bottom end you will probably find the idle air curcuit need readjustment. To repair this is very easy. The idle adjustment screw is mounted on the carb base and your owners manual should point this out. This is not the idle speed adjustment screw. The way to adjust it is to warm the motor up to operating temp, remove the motor cover and adjust the screw with the motor running and in gear. (Note:Always remember the number of turns you make) You will probably will find that by turning this screw counter clockwise about 1/2 turn the idle will pickup and she'll run smoother. Adjust it until the highest RPM is reached. The second step, if more is needed, is to lightly clean this curcuit. You remove the screw and lightly blow it off, and blow out the carb passage it fits in, with compressed air and a small nozzle. Squirting any carb cleaner (small amount) into this passage before blowing it out helps even more. All this can be done on the motor, hanging on the boat, quite easily. A owners shop manual will tell you all this in very easy to understand steps for less than $20 in most cases. I very seriously doubt that anything is worn out, need replacing or rebuilding. Period... The idle air circuit is most often the cause of these problems and is very easy to adjust. Ring back if I can help further. Ray S/V Speedy
A good portion of the soot on the plugs could be because of the way you have been running the motor at lower speeds. I would replace the plugs now so you can get a good plug reading in the future. Also run the engine much harder, it really need this at this point. Gas additives are not going to help at all in this situation. As for the roughness at idle and on bottom end you will probably find the idle air curcuit need readjustment. To repair this is very easy. The idle adjustment screw is mounted on the carb base and your owners manual should point this out. This is not the idle speed adjustment screw. The way to adjust it is to warm the motor up to operating temp, remove the motor cover and adjust the screw with the motor running and in gear. (Note:Always remember the number of turns you make) You will probably will find that by turning this screw counter clockwise about 1/2 turn the idle will pickup and she'll run smoother. Adjust it until the highest RPM is reached. The second step, if more is needed, is to lightly clean this curcuit. You remove the screw and lightly blow it off, and blow out the carb passage it fits in, with compressed air and a small nozzle. Squirting any carb cleaner (small amount) into this passage before blowing it out helps even more. All this can be done on the motor, hanging on the boat, quite easily. A owners shop manual will tell you all this in very easy to understand steps for less than $20 in most cases. I very seriously doubt that anything is worn out, need replacing or rebuilding. Period... The idle air circuit is most often the cause of these problems and is very easy to adjust. Ring back if I can help further. Ray S/V Speedy
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Alan
I would bring it back!
Did the dealer sell it "as is" or did he warranty it. If the latter, bring it back. You were sold something that at best may not have been stored properly and certainly was not prepped. At most I would change the plugs (gap them), change the fuel and hope. As for a 9.9 not being a good kicker, I don't think so. Maybe the guy wanted more but lots of people use 9.9s for boats up to 26 feet or more. Sorry for being cynical. alan
Did the dealer sell it "as is" or did he warranty it. If the latter, bring it back. You were sold something that at best may not have been stored properly and certainly was not prepped. At most I would change the plugs (gap them), change the fuel and hope. As for a 9.9 not being a good kicker, I don't think so. Maybe the guy wanted more but lots of people use 9.9s for boats up to 26 feet or more. Sorry for being cynical. alan
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Tom Wootton
Thanks all. Ray, you mentioned shop manual....
...I've been seaching this out on the web and there seem to be 2 available for Yamaha outboards: Clymer and Seloc. No customer feedback except one 5-star and one 1-star for the Seloc on Amazon. Prices are $25-30 plus shipping. Any feedback on these shop manuals? I'm leaning toward the Clymer, because there is one specifically for the 4-strokes. Alan, the motor is off warranty because I'm not the original owner, and it was bought just over 3 years ago. The original owner was planning to use it as a trolling auxiliary for his 225 hp main outboard, but found that the 225 could creep along just as well as the 9.9. Or so I was told. I'm relatively ignorant about sportfishing boats; I assumed most trolling motors were electric. Maybe someone is blowing smoke at me; but the motor looks brand new, and the aggravation involved in taking it off the boat and transporting it back to the dealer is more than I want to deal with unless there's something seriously wrong. Steve, I did talk to the dealer's mechanic today; he gave me a new set of plugs, and he suggested I try injector cleaner, the kind you mix in with the gas. He had not done anything to the carb, and the motor had been sitting at the dealer for 3 years, so cleaning seems in order even if it's not the immediate cause of the problem. If it doesn't help, I'll try Ray's idea about the idle air adjustment. For what it's worth, the mechanic offered a tip for starting the 9.9: he said before you crank it, put it in forward and open the throttle all the way twice, then return to neutral, point the throttle to the arrow and press the start button. Thanks again to all for your advice.
...I've been seaching this out on the web and there seem to be 2 available for Yamaha outboards: Clymer and Seloc. No customer feedback except one 5-star and one 1-star for the Seloc on Amazon. Prices are $25-30 plus shipping. Any feedback on these shop manuals? I'm leaning toward the Clymer, because there is one specifically for the 4-strokes. Alan, the motor is off warranty because I'm not the original owner, and it was bought just over 3 years ago. The original owner was planning to use it as a trolling auxiliary for his 225 hp main outboard, but found that the 225 could creep along just as well as the 9.9. Or so I was told. I'm relatively ignorant about sportfishing boats; I assumed most trolling motors were electric. Maybe someone is blowing smoke at me; but the motor looks brand new, and the aggravation involved in taking it off the boat and transporting it back to the dealer is more than I want to deal with unless there's something seriously wrong. Steve, I did talk to the dealer's mechanic today; he gave me a new set of plugs, and he suggested I try injector cleaner, the kind you mix in with the gas. He had not done anything to the carb, and the motor had been sitting at the dealer for 3 years, so cleaning seems in order even if it's not the immediate cause of the problem. If it doesn't help, I'll try Ray's idea about the idle air adjustment. For what it's worth, the mechanic offered a tip for starting the 9.9: he said before you crank it, put it in forward and open the throttle all the way twice, then return to neutral, point the throttle to the arrow and press the start button. Thanks again to all for your advice.
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Ray Bowles
Tom, I bought the Honda factory manual from
Honda dealer. Written for anyone to use. I do not know about Yamaha's manual. Ray
Honda dealer. Written for anyone to use. I do not know about Yamaha's manual. Ray
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Tom Wootton
Ray, if your engine is a Honda...
...does your advice about the idle air screw still apply to my Yamaha? If I recall correctly, the accelerator pump comes off the bottom of the carb; there were a couple of screws down there, but they didn't seem like adjustment screws to me.
...does your advice about the idle air screw still apply to my Yamaha? If I recall correctly, the accelerator pump comes off the bottom of the carb; there were a couple of screws down there, but they didn't seem like adjustment screws to me.
J
John
Remote Throttle
Tom, I have the same motor. It's a great motor and once you work at the bugs, I think you are going to be very happy with it. (I am with mine) Are you using a remote throttle? I know it took awhile to get my remote adjusted correctly (especially if its not a yamaha) You have to use Yamaha's adapters to connect the control cables to the engine. Aftermaket will not work correctly. You linkage could be binding when you move it into gear. Also, there is an idle adjustment screw behind the carburator that you may want to tweak a little to see if it helps the idling. Good luck and don't lose faith in the motor.
Tom, I have the same motor. It's a great motor and once you work at the bugs, I think you are going to be very happy with it. (I am with mine) Are you using a remote throttle? I know it took awhile to get my remote adjusted correctly (especially if its not a yamaha) You have to use Yamaha's adapters to connect the control cables to the engine. Aftermaket will not work correctly. You linkage could be binding when you move it into gear. Also, there is an idle adjustment screw behind the carburator that you may want to tweak a little to see if it helps the idling. Good luck and don't lose faith in the motor.
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Tom Wootton
John, I have the tiller...
...but I intend to change to a remote in the near future. I was leaning toward getting the parts from Yamaha, and you've convinced me. Where did you mount the remote lever? I also hope to devise a rudder-to-outboard link, as several others have done. But I'll have to address a clearance problem that wasn't there with my 8 hp Nissan. the narrow well of the H26 barely accommodates the Yamaha head, and leaves little room for turning. I'll have to offset the motor mount aft with some aluminum square tubing. Someone has a photo series on that, as I recall.
...but I intend to change to a remote in the near future. I was leaning toward getting the parts from Yamaha, and you've convinced me. Where did you mount the remote lever? I also hope to devise a rudder-to-outboard link, as several others have done. But I'll have to address a clearance problem that wasn't there with my 8 hp Nissan. the narrow well of the H26 barely accommodates the Yamaha head, and leaves little room for turning. I'll have to offset the motor mount aft with some aluminum square tubing. Someone has a photo series on that, as I recall.
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