guys
last weekend i bought a used 1988 yamaha 25hp two stroke short shaft outboard. its mounted on a very light 14ft aluminum jon boat.
it started up on the first pull at the guys house, and every time i tried to start it. runs good while idling and revving it up on the rabbit ears.
today i took it out for its maiden voyage. it started up on the first pull, then i got underway. taking it easy easing into the throttle. once i got going, i then went to full throttle.
the front of the boat came up, then went on plane pretty quickly. although it was going much faster than my old 15hp 4 stroke motor, to me it seemed like it wasnt performing to its full potential.
i was at full throttle for about 1 minute, then had to back off the throttle because of an under pass and bridge pilings coming up.
once i backed off to about half throttle, went under the bridge, then went to full throttle, nothing happened. it was kind of stuck at half throttle. the tiller grip was turning, but the engine was not responding. i kept backing off the throttle, and it was slowing down, then i tried to let it idle, and the motor shut off. i pulled it about 50 times and could not get it to start.
thankfully i had my *****ing motor to get me back to the ramp.
once i got home i wanted to flog the carbs with power tune spray, (as it had worked for me on numerous occasions,
i checked the air mixture screws (?), and the top carb was 2.5 turns out and the bottom carb was 1.75 turns out. i took them out, along with the bowl drain screws, flogged then thought both ports, put it back together with both at 2 turns out, and got it to start.... obviously it was smoking from the power tune spray, but once i got that cleared it would start on the first pull... i then flogged the carbs again with power tune and am letting it set for a few days.
i hope to test it again next weekend when i have time.
do any of you have any ideas as to what might be my problem ? is there different passage ways in the carbs for idle and full throttle, like an automotive carb ?
and what is the correct adjustment on the mixture screws ? i have them now at 2 turns out.
hopefully its something simple, and if i have to have the carbs rebuilt, hopefully that would be all that is wrong with it.
the previous owner said it had been setting in his garage for a while, and he always drained the carbs before setting for storage.
thanks for nay help you can offer.
last weekend i bought a used 1988 yamaha 25hp two stroke short shaft outboard. its mounted on a very light 14ft aluminum jon boat.
it started up on the first pull at the guys house, and every time i tried to start it. runs good while idling and revving it up on the rabbit ears.
today i took it out for its maiden voyage. it started up on the first pull, then i got underway. taking it easy easing into the throttle. once i got going, i then went to full throttle.
the front of the boat came up, then went on plane pretty quickly. although it was going much faster than my old 15hp 4 stroke motor, to me it seemed like it wasnt performing to its full potential.
i was at full throttle for about 1 minute, then had to back off the throttle because of an under pass and bridge pilings coming up.
once i backed off to about half throttle, went under the bridge, then went to full throttle, nothing happened. it was kind of stuck at half throttle. the tiller grip was turning, but the engine was not responding. i kept backing off the throttle, and it was slowing down, then i tried to let it idle, and the motor shut off. i pulled it about 50 times and could not get it to start.
thankfully i had my *****ing motor to get me back to the ramp.
once i got home i wanted to flog the carbs with power tune spray, (as it had worked for me on numerous occasions,
i checked the air mixture screws (?), and the top carb was 2.5 turns out and the bottom carb was 1.75 turns out. i took them out, along with the bowl drain screws, flogged then thought both ports, put it back together with both at 2 turns out, and got it to start.... obviously it was smoking from the power tune spray, but once i got that cleared it would start on the first pull... i then flogged the carbs again with power tune and am letting it set for a few days.
i hope to test it again next weekend when i have time.
do any of you have any ideas as to what might be my problem ? is there different passage ways in the carbs for idle and full throttle, like an automotive carb ?
and what is the correct adjustment on the mixture screws ? i have them now at 2 turns out.
hopefully its something simple, and if i have to have the carbs rebuilt, hopefully that would be all that is wrong with it.
the previous owner said it had been setting in his garage for a while, and he always drained the carbs before setting for storage.
thanks for nay help you can offer.
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