How To Fix Yamaha 25hp 4 stroke Outboard Acceleration Issue

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[skaterfrederik]

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 ❤️

[dinghyride]

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

[ricardiac]

So I tried it... Worked awesome!
I ultrasonic the carb with the old jets... No change.
Installed the described jets... Perfect.

[marklandry]

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

[bsrktm]

Did you check the accelerator pump? I've repaired several F25s with clogged/bad accelerator pump systems and they all hesitated like that.

[manko]

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.

[wmkess]

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?

[peacepeaceful]

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.

[jpconga]

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

[kkelly]

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.

[benb]

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.

[edgewatersbestguitarist]

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

[rouddypierce]

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.

[MrSparks]

Thanks for the video Eric. Where do you get your outboard knowledge from?

[jameshinson]

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

[quietwyatt]

Well done - great info.  what year is that 25hp.?  I'm looking at a boat that has a 2002 Yamaha 25hp four-stroke tomorrow.

[onat]

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

[HWoodCreations]

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?

[gottabidonthings]

we are supposed to bleieve the factory let this go ? not bloody likely bro

[USMC-]

When you have to remove the carburetor it's a little easier to just unscrew the manifold then you dont have to worry about getting that long bolt in the back iit can be a pain in the butt .