Hello guys,I looked for this topic, but i didn't found the answer.I try to explane my problem. Sorry, my english is not so good...I have a Yamaha F100 four stroke from 1999. The boat is a normal console boat (5 meter, 470 kilogram). The prop is a 19 pitch.When i give (from stationair trottle in forward direction) in one time full trottle, the motor has a little dip (1 second or so). It seems it has too little fuel. That is the only dip in the rpm range. When the nose is down, no problem anymore. Normaly i give first half trottle, then full, also no problem. Only when the motor from 1000 rpm to full trottle.I think it is better when i give quite trottle than trottle in one move, but maybe i can fix this problem easily.Thanks and greetings from the Netherlands,Mish
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Re: Yamaha F100 acceleration dip (solved?)
It sounds like your carbs may need synchronizing. That's something you need equipment for. You can't do it yourself without it. Also try running some automotive fuel system cleaner in the gas. That may help dissolve any varnishing that may be restricting a passage in the carb.Your English is Fine!
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throttle lag is very common on 4 stroke carburated motors, if its not actually spitting back or backfireing its most likly normal. there is an accelerator pump setup to help make the fuel go richer when rapid shutter opening occurs. next time your in a manual shift auto, place the transmission in high gear, at 1000 RPM floorboard it rapidly and see if it lags and see how long it takes to build up RPM. that boat motor is fighting the same problem that car motor is. do you have the F100 service manual?
He Guys,Thanks for the responding, glad that my english is not so bad.. Willy@ next time i try automotive fuel system cleaner in the gas. Thanks for the tip.Rodbolt@ The motor runs very smootly. No spitting back or backfireing or something. On every range there is no problem, only with a low RPM. I tried also a higher RPM (1200). The throttle lag stays. I think by 2000 RPM the problem is solved. I must try it next time.I have no problem with it, if it is a common problem with the carburator 4 stroke. Normaly i move smootly the throttle open. But, if it is not normal, i want to solve it...I have only a owner manual. I want to buy a F100 service manual (technical part for mechanics?). Prefer dutch Thanks for all the respons!Mish
Hi,Also make sure You do not have any water in fuel. Use a fuel/water separating filter (like Racor or orginal Yamaha filter - basically same by the way, Racor makes almost all such filters). I belive service manuals for Yamaha outboards are only available in English.
Yep, i have allready a seperate 'water filter'. If there is water in the tank, can that be the reason the motor has a throttle lag on a low RPM?When i bought the motor, i tried it behind a other boat.I was a passenger and i didn't notice the throttle lag. Maybe there are more reasons...A service manual is only in english? Allright, it is good for me. Thanks, Mish
The F100 had a dip when I the motor runs stationair (1500 tpm) and i gave full throttle. When the motor runs 2000 tpm, the problem solved.But later...The F100 runs stationair a little bit too hard (1500 tpm). I turn the black stak at the end of the trotlle cable a in (it makes the cable a litlle shorter). After this modification, the dip disapeared! Is it possible when the throttle cable is too long, the valve in the carburator (when i give full throttle) does't stand right? Maybe the valve go too far...? I dont know.Ányway, the problem is solved!Thanks, Mish
Yamaha F100 acceleration dip (solved?)
I looked for this topic, but i didn't found the answer.
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