How To Fix Yamaha 25hp 4 stroke Outboard Acceleration Issue
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- čas přidán 1. 01. 2016
- If you own a Yamaha 25hp 4 stroke you may experiencing acceleration issues and this is a factory defect. To solve the issue you must replace the jets. We are moving up from a #108 main jet to a #130 main jet then we are moving up from a #45 jet to a #62 jet. The part number for the jets that you need is 6H4-14948-12-00 and 676-14943-33-00 and you need 1 of each jet. Boats.net is a good place to buy these jets.
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CAUTION! I think this is improper advice. I had the EXACT same issue with the EXACT same engine that had IDENTICAL symptoms. I saw this video and thought a ha! This is the problem. But a experienced mechanic showed me how to fix it otherwise. I took the carb out, and ran through a ultra-sonic parts cleaner with a Simple Green solution(3 times actually) and it fixed the engine perfectly, returning to like-new performance. I think this "change the jets" is a less-than-ideal workaround of a clogged jet issue. If you are experiencing the symptoms in the video, dont change the jets, just buy a heated ultrasonic cleaner, and let it clean overnight. Bigger jets will change the fuel consumption, change air/fuel ratio, and wont return engine to full performance. cheers Conor
I’ve had the exact same problem with my Yamaha f20. It turned out to be a clogged acceleration pump. As its made to need more gas right away when you open the throttle, to give it a Quick response, it Will make sense if that canal is clogged too, in this video. As you Can hear, the engine revs up quite slow after the fix. I guess you made the engine work, but now it Will drink more fuel while rev’d up. A better fix would be to clean the acceleration pump canal, to make it drink less gas and respond quicker.
Amazing videos btw! We need more ❤️
So I tried it... Worked awesome!
I ultrasonic the carb with the old jets... No change.
Installed the described jets... Perfect.
Behind that very first screw that you loosened to remove the linkage is a small plunger with a bellows. Odds are that this is stuck due to fuel residue… with the throttle open, take a small screw driver or knife blade and move the plunger down. Do this until a couple of times until it moves on it’s own when you open the throttle.
Even with your larger jets, it still hesitated noticeably… I’m twinging that there lies your problem. If it does improve it or fix it, you should still remove the carburetor and clean everything
Tried that as well.. plunged well.. jets made a night and day difference
Just been searching for an issue with my yam 40hp. Idles fine. Put it in gear and excellerate its holds back a little. Up the revs she flies along.
Im.guessing those jets were an idle one and one for open throttle?
How did you know what size to move up to?
Good vid..even this late in the day.
Where did you find the jets?
Where to buy those jets please
Yamaha would not build a motor that will run like it did previous to the jet change.Disassemble dip in carburetor dip spray all the cleaner out with the water hose then the water out with the air hose be careful not to loose any parts reassemble and it will run like new. The accelerator pump was clogged on that motor. You do a good video but I would research a little more if you want to keep your motor stock and running in it’s intended form. Just saying.
I just ordered my jets. I have the same motor with the same problem. Hope it works for me too
that size jet hole look smaller than the ones i took out
Where did you find your jets?
i have the same issue
Not buying that I'm afraid.yamaha wouldn't send motor's out from the factory like that there's something blocked or air leakage or excelorator pump faulty.you should find the problem not over compensate it
sorry but misleading video , you you haven't diagnosed the problem , you've just tried to override it.
stil bed...
WHAT??? This video (and motor) are only six years old and the motor is CARBURETED?? Since when? Four stroke, EFI motors have dominated the Yamaha product line for well over 15-years, so why are we focusing here on a carbureted motor?
Nicely done. do you know of any other particular year models that run into this problem?
I have a 2013 similar to yours and haven't noticed it yet but if i had I would have blamed it on a dirty carb and cleaned it, never realizing using different size jets.
Had the same problem.On three yamaha four-strokes.25hp,6hp,2.5hp.Problem is not the jets but when you pick up the motor the dealer (Lazy) only does a fast start up and oil run . DO adjust the carb slide and adjust the idle screw plus the throttle cables.The four stroke`s run cold warm up first then adjust everything. Watch my new yamaha 6hp portable and did a test ,the motor idles and picks right up on plane.Runs perfect.
How is it that the factory jets are undersized? Did every motor from this year have the problem or did a previous owner tinker with it and put some undersized jets in it?
wmkess they aren't. That fuel restriction comes from swollen gaskets blocking fuel passages. Now his motor will crap out at full throttle drinking more fuel than it can get
Thanks for the video Eric. Where do you get your outboard knowledge from?
I learned over time
There is something else going on with this motor. Factory jets should not be running like that. You may have an air leak that likes the bigger jets but that still doesn't fix the problem.
My 2004 yamaha 50hp jets get clog all the time since new. New outboards use thin jets for fuel economy but they clog ease. Old outboards don't clog that often because low jets are bigger and use more gas also
Well done - great info. what year is that 25hp.? I'm looking at a boat that has a 2002 Yamaha 25hp four-stroke tomorrow.
this is a 2010 i think
Nice video but i wished at the end you put “before” and “after” results, would be better
Just curious here? When you have laggy acceleration (like you had), that usually means you have a clogged or dirty Main Jet. So, you should just clean it. Otherwise, maybe an air leak (unlikely, but could be). So, why would you go up THAT MUCH on a motor (specially in Florida)? I understand if you took a motor from FL, and took it to Minnesota during the winter, you should go up a few on the jets, but THAT MUCH, for a FL motor? Damn bro.... That's crazy... I honestly wouldn't do it!!!
Did you check the accelerator pump? I've repaired several F25s with clogged/bad accelerator pump systems and they all hesitated like that.
What is an accelerator pump? where is it located?
@@kennywatzke1416it squirts extra fuel into the intake as the throttle is opened. This is because the carb will lean out momentarily and hesitate.
A plunger on the side of the carb is the location- a black rubber boot covers the plunger. Carb bowl must be removed to access the plunger.
I've got a 2002 Yamaha 15hp 4-stroke that's doing the exact same thing. Would these jet sizes work for for a 15 hp?
Hi Eric, Great work. I have 2014 model Yamaha F25DETL. This change is valid in 2014 models and what is the fuel consumption increase? greetings from Turkey
D: ! Oh god! Dude no. That top diaphragm gasket has swollen and stretched out and it can't get proper air/fuel through those passages The SV carbs on johnson/Evinrude motors have a plastic top that warps with ethanol fuel use and gets an air leak. The accelerator pump on the side that plunges down and shoots extra fuel at first throttle will, guess what, leak air. And it needs that pump for quick proper response. This extra fuel use will make it "skip" at full throttle drinking more than it can receive through the inlet. Like setting a float too low
Hi, sounds like you know what you are talking about👍🏻 can that top diaphragm gasket be replaced?
Where did you get the over sized jets? And that rubber plug over the smaller jet what is it for? I took the carb apart and forgot to pit it back in the port and it stoped the problem. Realized the plig wasnt in so i took the carb apart again, put the plug in and the problem re occured
I'd like to know the answer to that. Why is it there?
Big Kahuna so i tool my carb apart again and there is a hope from the small jet to the big jet so it must be a bypass plug but my outboard ran like a champ when the plug was out
i bought a motor once and it would bog down at open throttle turns out the carburetor was missing the plug. that plug controls the amount of fuel that goes in to the jet. it kind of looks like a fuel restrictor
If there is a plug then it is designed to not flow through that spot. If it worked better without, you got lucky cause there is a problem somewhere else. I love his videos but he way over shot what was needed for jetting increase. a couple of #'s on each would have been a ton. When you increase the pilot jet you can expect to have to dial the pilot screw back in some too. It should be an effective tuning screw in the 2-3 turns out range if the pilot jet is right.
This is why you change out the fuel filter regularly, gas tank after awhile, and gas lines too, garbage will eventually make it's way into the jets. People don't do preventive maintenance and this is what will happen, you'll be shutdown.
What sort of camera do you use to record these ?
we are supposed to bleieve the factory let this go ? not bloody likely bro
I have the same problem with a brand new 2.5hp Yamaha, out of the box. The dealer is 50 miles away from my house. Damm it !
I don't think you've cured the issue, I cannot see Yamaha sending out engine's out with incorrect jets fitted ,every engine is run up, tuned and adjusted where necessary .Your rarely get it wrong normally.
BAD INFORMATION!!!
I know this because I know how to fix the "acceleration issue". It's not hard, but time consuming, tedious, and you need some tools. There is NO FACTORY DEFECT. The "issue" is caused entirely by either poor fuel quality or staled fuel from sitting, or occasionally debris-but even the factory filter/separator that's mounted to the engine does a pretty good job of removing the junk from fuel. I've never seen one with garbage in the fuel bowl, but I've seen PLENTY with staled fuel from sitting. I will not discuss how to properly fix it because people will run out and ruin their carburetors and then blame me for THEIR mistake.
Larger jets will (1) increase fuel consumption (2) increase emissions (3) potentially foul spark plugs, (4) decrease your top speed-perhaps drastically-and (5) make every technician that has to work on it chase their tails AFTER cleaning the carburetor properly, which you (the end user) will have to pay for the additional labor. Oh, and let's not forget that the increased emissions could potentially set you up for liability issues if your state or locale were to press the subject. (Kalifornia?)
This video doesn't address several things. His "fix" is a hack fix. The real fix is to clean the bowl passage, which is impossible without drilling. What he is doing is bandaiding a fuel-starved accelerator pump by increasing the fuel that flows through the jets, which is, again, incorrect. While it works in his video, I know firsthand what the real fix is and the gentleman in the video did not do a proper job of showing that proper fix. Did anyone notice in the first part of the video that he's running the engine with the fuel line disconnected? Did you hear the fuel pump clicking? That's the first thing I noticed...the carb was starving for fuel already and he's blaming it on a "factory defect"? Or perhaps his idea of a factory defect relates to the tiny orifice that's BUILT INTO the bowl, and plugged. I can nearly place a 100% guarantee it ran fine the first time it came out of the crate, then perhaps it sat up for a year or 3 and that's when the "issue" started.
The idle speed is adjustable, but again, I ain't going into how to adjust it. Also, the orifice in the bowl is cleanable but just like I said before, it requires drilling. Then there's the accelerator pump tube that gets plugged with staled fuel and can cause issues. Oh, but that's not even considering that the bowl gasket itself (o-ring) tends to flatten/shrink and will leak fuel, but because the fuel is fed in from the bowl, through the gasket, and then into the main body, if the gasket doesn't seal, it will overflow the bowl making you think the float valve is leaking.....oh the joys of working on these for a living. You learn things. Wait til you do a carbureted F40 (4 cylinder or 3 cylinder) or an F50 carbureted engine. Those are really fun.....and to do them properly, in other words, restore factory running condition, they're time consuming.....which means labor...which means several things. Cheap isn't always good. Better know someone who knows their stuff because on the F40 and F50 4 cylinder engines, the engine can hole pistons if the carburetors are not perfectly tuned; and they aren't cheap to replace powerheads!
Turbo Joe Hi Joe, read you input on this old video. You have any info on where I can find info on doing the carb compleatly witbout having to "blame" you if I mess it up? Mine is a 1999 65w f25ae and it idles great and runs perfect on higher revs but cuta out when increasing revs from idle. Thanks in advance!
peter merian A Clymer repair manual will tell you everything you need. Spend the 50$ and get one for your motor
Thank you for the right info. Or some of it lol
My 2015 15hp does the same thing. I just cleaned the carb and jets yesterday. I might have missed something. Other then this issue it runs amazing. I doubt that the jets need to be upsized
You did not even clean the carb with any carb cleaner the dirt might still be in there
There's a lot more wrong with his "repair". This is the kind of thing that I see often from those repair shops that appear and disappear in a month's time. Unfortunately, the low price sells their service more than their tech's knowledge does.
Hey Eric you need to learn tje names of the tools you use... That's a quarter inch drive 6" extension and a quarter inch drive universal joint... Not "one of these"...