need advice on Yamaha motor

I have a 98 200 VMAX that bogs down a split second after giving it full throttle to put the boat on plane. It starts and idles just fine but seems like its running on 4 cylinders instead of 6. Every now and again it will kick in and go for a second or so and put you into the back of the seat as it should…I have also lost about 10-15 mph on top end…It seems to run semi smoothly when on plane but theres definitely the speed loss factor. I need to prefish for some tournaments so I don’t want to take it to a shop so I am looking for some input from you guys. I took all of the plugs off and none of them are fouled out so I am thinking its a fuel related issue or something possibly electrical like a coil or something? I’ve never had to pump the fuel bulb and I did while out the other night and it took about 50 pumps to get it solid and it made no difference in the way it ran.

thanks!

Possible fuel filter issue? If you haven’t checked in a while I would.
Hope this helps!
Eric

How ’bout an air leak in the bulb? Shouldn’t need 50 pumps to get her tight. You should have seen gas coming from somewhere after pumping it that long…….

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How ’bout an air leak in the bulb? Shouldn’t need 50 pumps to get her tight. You should have seen gas coming from somewhere after pumping it that long…….

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Fully agreed on that!

Sounds like when you put the “quick screws” to her, that fast draw of fuel is creaking an air suction somewhere that causes the hesitation.

you guys just might be on to something…I’ll check her out!

It never crossed my mind that there was an air leak or something in one of the lines even though it took that many times to pressurize.. I hope its something as simple as that!!!!

this brings me to another question…I’ve had the boat for 3 years and it came with a hotfoot installed..It has always taken around 2 seconds after I “give ‘er the onion” before anything happens, i.e the motor kicks in…Is this because of the hotfoot? I would think I should be seeing an immediate response. I had the motor rebuilt last year after blowing the powerhead and its responsiveness was the same as before

Hmmm I’m thinking of a couple things…. (not that the other suggestions aren’t worth checking)

First off is this an ox66? if so I think it could possibably be the o2 sensor, do you run ringfree or seafoam in everytank? The article HERE can help you clean and trouble shoot it. Not sure if the hpdi’s have o2 sensors, I think they may have atleast at some point…

Secondly have you had any fuel pumps replaced? if not it may be time for them, they seem to be good for 4-5 years or so on most motors.

Thirdly another thing that could be causing this is debris in the VST tank. I copied someone’s post from another forum….

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The VST has to be taken apart and cleaned out if there are any deposits or varnish in it. The filter screen on the electric fuel pump is probably also partially obstructed. Sometimes you will just see a pile of debris under the pump that gets “sucked up” if conditions are right. Be sure to change the expensive “oring” seal on top of the VST and the also expensive fuel pump filter while you are cleaning everything

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Edit: I just found a link explaining this…. http://bbcboards.zeroforum.com/zerothread?id=66928 Aweful good yamaha forum on there, pretty much where I learned about everything I mentioned…

thanks Nick, I’ve been trying to get on the BBC boards for the last couple of days, but my work computer won’t let me for whatever reason.

My Yamaha is a carbeurated 200. I think the OX66 is fuel injected? Another thing I have run across is the O2 sensor being dirty as well. All along I thought it sounded like a bad fuel pump but I am going to start by eliminating all of the lines to the motor and go from there. Thanks for your input!!!

Quote: thanks Nick, I’ve been trying to get on the BBC boards for the last couple of days, but my work computer won’t let me for whatever reason.

Couldn’t be because they want you to work at work?

Had a nearly identical problem with my Yamaha 150 4 stroke earlier this summer. Dealer told me I needed the new Yamaha fuel filter system, so $150 later, my problem was still not fixed, but I had a nice new fuel filtration system. After some head scratching and thoughts of taking it back into the shop, I decided to try 4 new spark plugs. Problem fixed…now smooth as silk just like when new. For the little bit it costs, it’s certainly worth a shot. Good luck.

NWBuck

Its your fuel pumps! not the highpressure pump but your lift pumps! this is y it will run fine on idle but as soon as you gun it the lift pumps cant keep a supply of fuel to the high pressure pump! this is y it will take off for a second and then die out! and when your on plane running if you drop back on the throttle it will probably go ok but if you give her the nads im sure it just seems like the power isnt there!

lift pump are a simple rubber diaphragm and should run ya around 50 bucks to fix!

good luck!

another thing that says its the lift pumps is the fact it wont pump up! the diaphragm is riped and you have to pump and pump to fill all the lines and the highpresure pump reservoir!

one way to know for sure is to take a buddy out with ya and run her!@ when it start to die out and seems there is a loss of power have him pump the fuel ball and see if there is a second of regained power!

by pumping the ball you are doing the job of the lift pumps!

Your primer bulb should never a I mean never get hard.
A 98 v-max? Is it carberated or efi? A hard bulb on a carb motor means a stuck float or bad needle and seat.
This motor needs to go to the dealer- sounds like a linkage sync. problem. I know-get an evinrude!