yamaha starting problem

[ransboat]

year 2000, 225 Vmax wont start when hot after setting for 20 minutes plus, unless I give it some gas and crank it a few times. After it starts, I have to rev up the RPMs to clear it out and it smokes for a little bit.No problem when starting cold or restarting immediatly after shutting the engine off. I had the plugs, main fuel filter, primer bulb, crank sensor, and O2 sensor replace. Not all at once, just trying to fix the problem.I have recently taken it into a dealer (only Yamaha authorized dealer I could find in NM) and waiting on them to look at it. Any idea on what could be causing this. I would like a little heads up on what might be happening.thanks

 

[k4ubr]

Re: yamaha starting problem

i would pressure check all lift pumps (3)

 

[rodbolt]

Re: yamaha starting problem

yep look at the lift pumps or a leaking injector or a bad needle valve or pressure regulator.
by having to open the throttle you are allowing more air into the intake.
means the fuel mix is rich at a hot restart.

 

[ransboat]

Re: yamaha starting problem

Thanks for the recommendation, I will look at these items and let you know. Sorry for the late response

 

[ransboat]

Re: yamaha starting problem

Rodbolt, The boat was at the shop for over a month and still no solution to the problem and I got tired of waiting on them to give me an answer. I took the boat out again to see if I could identify any additional details to give you. This time out I still had the starting problems, however now have a additional problem. Running down the lake everything was good and all of a sudden it stalled for a second then picked back up again and continued down the lake.This did happen once prior to taking it in but I thought it might have been a isolated incident. After setting for awhile (engine off), Started and as soon as I started to plane the engined stalled out. Restarted fine and could rev the engine in neutral, however evertime I was about to get on plane it would stall. Started the engine and pumped the primer bulb a couple of times and then it would get on plane and run fine. It seemed that as long as I pumped the primer bulb while ideling it would not stall when going to plane. I did put fresh fuel in prior to getting it out this time. In the mean time I did order 3 new fuel pumps, since I did read that this engine seems to eat them every 3-4 years and these are the original pumps. I always add ring free to the fuel and have since new. I thought I would give this a try before I take it to another authorized yamaha repair shope 300 miles away. Thanks in advance

 

[rodbolt]

Re: yamaha starting problem

install the new pumps and clean the vst replacing or cleaning all filters and orings as nessasary.
myself I would send the injectors to a shop like flagship marine for filter replacement and injector leak and flow testing.

 

[ransboat]

Re: yamaha starting problem

thanks Rodbolt

 

[ransboat]

Re: yamaha starting problem

Rodbolt. I replaced all three fuel pumps,and cleaned the VST tank. This solved the problem and when I took the old pumps apart I found a few tears in a couple of the diagrams. Thank You for sharing all your knowledge. The boat ran great for about 4 seperate outings with no problems until last week at Amistad after a couple of days of running the lake. One afternoon I was running about 3/4 throttle and it lost some power. Now I am running about 10 mph top end less than before and the engine sounds like it is missing (like a bad plug). I did put new plugs in earlier this year and have not checked anything yet since I just returned. I am also thinking it might be a bad injector, however before I start dumping money into it like before I would like to get your advise. I did not send the injectors in for testing and cleaning since the fuel pumps solved my last problem. Also, the boat is smoking more than normal with a white color. Any advise? Thank You

 

[rodbolt]

Re: yamaha starting problem

test the compression, test the spark and reclean the fuel system you can replace the injector screens with mercruiser part number 35-17422

 

[ransboat]

Re: yamaha starting problem

thank you. I will give it a try

 

[ransboat]

Re: yamaha starting problem

Rodbolt,
I checked compression-good, checked spark-good, and replaced injector screens. I was finally able to get the boat on the water to test yesterday and still not running to full capicity. Top end is about 15 mph short and it still feels like it is missing and running rough. Does not appear to be smoking while running. I pulled the injectors today to send off to the company you mentioned for testing and cleaning. When you refer to cleaning the vst tank, what exactly are you referring to? Also, any other recommendations? This is driving me nuts. Just a note, when I pulled the air box off, I noticed what appeared to be more than normal fuel/oil on the air intakes. Thanks for your help

 

[rodbolt]

Re: yamaha starting problem

fuel and oil in the air box is normal.
the VST is that aluminium tank on the port side of the motor.
it also has a pressure control valve.
the VST is where the high pressure pump intake screen is located,if its restricted fuel rail pressure drops and cylinders run lean and pistons pop shortly thereafter.
the regulator also has a screen that if restricted increases rail pressure and creates a rich conditon thats lean on oil.
a defective or incorrect voltage output from the O2 sensor can run lean above 4000 RPM.

 

[ransboat]

Re: yamaha starting problem

Rodbolt, I replaced the high presure fuel pump filter a few months ago prior to replacing the low presure fuel pumps. I have not checked the presure regulator screen and will pull that and clean. Also, I will check the high presure filter again and see if maybe something dislodged when I replaced the other pumps. Do you still recommend sending the injectors in for testing and cleaning?