I have a 4 year old Yamaha 225 4 stroke. I have had several problems with the engine stalling. On restart it sputters but will not run even after pumping up the primer bulb. It's been in the shop twice. The fuel/water separator was replaced the first time and the second time the mechanic said he found a kink in the fuel line which he corrected. But the problem persists. The last time it stalled it did restart after pumping up the priming bulb, but I have lost confidence in this engine. I boat on the Cheasepeake Bay and an unreliable engine is a BIG problem. I'm considering putting in another fuel line and bypassing the fuel/water separator on the theory that there is too much pressure drop in the fuel line to the engine. Any ideas?
I had a fuel problem with my 03 f225 would only stay running if you pumped the bulb,stop and it would die. Ended up being the secondary fuel pump. turn the key to on position and see if you can here it run, it will only run for a second or two. This is an expensive guess.
find a real dealership and quit guessing.
ALL yamaha dealers were shipped a fuel system tester as part of the essential tooling, your not asked if you want it or not you just get it and are billed.
this tester allows for checking fuel system vacum with the hull on a trailer and the engine off.
then on to the electric lift pump, this is the externally mounted pump, it runs 10 seconds on and 20 seconds off at low speeds, it can be tested with a fuel pressure test guage at the output side once the supply side is tested, it can also be checked electrically with a multimeter while testing the output.
once the low pressure fuel side is confirmed or eliminated repost with the test results.
use the Yamaha dealer locator for your area and find a shop with a master tech or at least look for the school certs on the wall for 4 stroke,electrical and fuel systems.
there are a few other reasons for sputtering and stalling at idle, some are difficult to find but not impossible.
these all sound very familar, my 02 F225 does the same thing. i have been told it may be due to a vapor lock. I just found out about a technical bulletin that Yamaha sent to the dealer on 9/23/03. They have a vapor recovery kit that is suppose to cure it. of course, mine is out of warranty now and they want $500 to install the kit. I think they may be in for a little battle with me as no one told me about this earlier. this is not a new issue for me.
My Yama mechanic is ok for basics but not greatest. Have a 03 Yama 225/4-str that, after sometimes 10 min or 30 min at idle/slow speed, sputters. If I don't throttle up quickly it'll stall. I'm quick enough when at slow speed, but at idle it stalls as not much room for lesser RPMs. Usually starts back up again with no problem. Had initial very bad batch of gas when bought boat and tank had to be drained, so think debris might be clogging intake in tank as engine runs great at every speed other than idle/slow. Hate to go through expense of tank cleaning if no need. Would fuel tank breather hose stall engine if kinked/soft? Rodbolt's 7/7/08 comment about the external mounted electric lift fuel pump that runs on for 10 sec and off for 20 got my attention. Installed Racor fuel/water filter and change every 50 hours. Always keep tank at least half-full and add stabilizer as live in south FL and don't want condensation/ethanol. Anyone have any ideas?
Check you motor mounted fuel filter. If you just changed it or took it of recently this might be your problem. The cups can swell due to ethanol and can cause a small air leak when you tighten it back on. Look at the filter while running and if you see the fuel level drop in the cup and then start to sputter this is most likely your problem. Good luck getting this resolved!!
Common problems that are easily fixed to cure stalling at idle speeds are usually a weak primary electric fuel pump or fuel level in hose dropping back into fuel tank while primary pump is in OFF mode.
Hook up a fuel pressure gauge to the fuel rail to monitor the pressure that the injectors "see".
Temporarily hook up a clear fuel line from your primer ball to the fuel inlet filter on the motor.
Idle the motor and watch the fuel level in the clear hose. As the primary pump cycles on and off, you may see the fuel run back out of the hose, back into the tank if there is no anti-siphon valve installed. As the electric pump fires up again, it runs dry until the fuel is pulled back up the hose. That results in less and less fuel delivered to the VST and then on to the injectors. You will also see a drop in fuel pressure when not enough gas gets to the injectors.
At higher speeds, the electric pump runs continuously so the problem does not occur. You can also monitor the pump output pressure to make sure the pump is in good health.
If either condition is found, it is a good idea to replace the "F shaped" filter between the pump and VST.
Seahorse I have had this same problem with my motor and the mechanic did the tests you just described and changed the F shaped filter. After that I ran 40 miles offshore and trolled for 2 hours with no problem then it started again?? When it stalls and I pump the ball sometimes it feels like its all air and the ball will get to the point where it wont pump anymore. Shouldnt the air pump through the fuel system? I cant understand where the air comes from, Everything has been replaced from the pick up tube to the motor. It is like the air is building pressure from the motor side and pushing it back towards the tank. I have observed the clear filter mounted on the motor and at idle the low pressure pump will come on every 20 seconds or so and the fuel level will drop about a half inch then when it shuts off I can see fuel being pulled in from the line from the filter. I have been dealing with this for 6 months now and I have been to 3 different mechanics with no luck and I have searched the net for weeks now and when I saw your answer about the F shaped filter which was the only thing that has temporarily helped, I had to ask you what causes this issue? Thank you for any help you can provide
I had the same exact problem with a 03 225 yama/merc which is a yamaha engine with a merc cowling. It ended up being the VST filter. There is a metal cannister (Vapor seperator tank) that the fuel pump sits in, and on the bottom there is a tiny (and expensive) fuel filter they call a VST filter. It just pops off the bottom of the pump. I was having the exact same problems, and after i changed that filter it has run great ever since. Good Luck