How do you fix an engine problem on a Yamaha waverunner?

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Hi Howdy,


First and foremost it sounds like you need a carburator cleaning. You need to remove them & disassemble them completely to clean them thoroughly. This is a kind of preventative maintenance that needs done every season, if not more often. I'd clean mine every 20 hours that I rode. If the boat sits for any more than a month between rides I'd do it then too. Carbs get clogged up pretty easily.

The white smoke is a product of your mixture being oil richened by the lack of gas running into the system because of a clogged pilot jet. Worst case scenario is that the white smoke is caused by a bad head gasket, but I'd clean the carbs first & see how much it improves.

I can give you a walk through to get the carbs off if you are going to do the work, but if you aren't it is a lengthy write up. Let me now if you need instructions, thanks.

Edited by Lori-Moderator on July 29 2007 at 2:30pm

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Brian,

Can you please give me the instructions to cleaning the carbs and how I am supposed to get them off the waverunner.

Thank you.

Hi,

This is a pretty involved procedure that requires some decent screwdrivers, both phillips & slotted, some small metric wrenches(6&8mm), a decent small brass punch, a good bit of time, a clean work area, a good dose of mechanical ability, and patience.

This a pretty generic set of instructions but most all watercraft, motorcycles, snowmobiles, & atv's have the same basic set up.

I recommend that anyone attempting to work on their own vehicle purchase the factory service manual for that vehicle as it is sure to have critical model specific instructions that may not be here. If you have done carburators before it is easy to figure those things out but keep in mind that not even the service techs at the dealer do it without the manual. And they are trained mechanics.

To start:
You will need to disconnect the negative battery terminal.

You will then need to shut off the fuel supply either by it's valve or by pinching the line from the tank to the carbs. After it's pinched or shut off remove the line feeding the carbs.

Next will be to remove your airbox, I would simply just loosen the boots that are on your carb mouths & take the whole airbox off, remembering & noting where any & all hoses attach.

After the airbox is out, note the location & routing of the throttle cables & remove them from the carbs, I label them as to not mix them up during reassembly.

Next, loosen the intake boot clamps from the outlet side of the carbs and your carbs will slide out. Pull on them nice & evenly as not to cock them in the boots. When you reinstall them put a little grease on the lip of the carbs or on the inside of the boots, they will slide right back in nicely.

Now that your carbs are out, drain off the gas that is in them by the drain hose off the float bowl or flipping them over a drain pan.

Now flip them upside down onto their tops on your neat & clean work area. Remove the float bowls and you will see your float and your jets. Sometimes especially on Mikuni carbs you need to remove the float to get to the intermediate jet. You will need to tap out the float pivot, that will usually only go in or out one way, they are usually tapered, some carbs have arrows some don't. After the float is out of the way you will see your jets and should be able to get them out easily. They are brass so be careful not to ruin the screwdriver slots or break off any little pieces that can get stuck in the jet. Your main jet usually requires the wrench.

After you have removed your pilot, intermediate & main jet soak them in some carb cleaner. Keep good notes on their location as pilot jets & intermediate jets will readily go in each others place and you won't know it until you try to run the boat.

*** I think you can stop here, & just spray off the carb body & blow it dry, spraying quite liberally into the carb and all it's holes. If you see that it is still very dirty proceed with the next steps*** Definitely read the rest, but you may not have to take the tops off.

Then flip the carbs back over and take off the tops, remove the diaphragm, the spring, retainer & needle or the slide. You will now see if you have an adjustable needle, if it doesn't have a clip it is not adjustable. Moving the clip up lowers the needle allowing less fuel through, moving the clip down raises the needle allowing more gas through. Less is leaner, more is richer. Now they are mostly disassembled & ready for the spray cleaner shower.

*****A word of warning on Yamaha's Mikuni carbs. The slide may go in in either direction. It is up to you to note it's direction & make sure that they are installed in the proper direction. If they are installed backwards you will get major headaches trying to figure out why your boat won't run or starts and idles at 5000.

****Another non user friendly piece on these is the throttle position sensor on the side of the carb. It is the only thing that has wires to it, disconnect the connection but I would not remove the tps from the carb body. Because you are not removing the tps from the body you will only be able to use spray carb cleaner that is not crysillac acid. DO NOT USE B12 CARB CLEANER, I recommend CRC Brake & Parts cleaner, or CRC Carb spray.

Spray them liberally & used only compressed air to blow them dry. Do not poke anything into orifices in the carb. Also only spray out your jets, do not poke anything through them.

Assembly is the reverse sequence.

I recommend that on motors with more than one carb that after a rebuild they get synchronized with vacuum gauges to maximize the performance of that set up, and really get both carbs working together.

If you need anymore info please let me know.

Edited by Brian on July 30 2007 at 10:57pm

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Hey,

Thanks for the instructions on how to fix this problem.

Is it possible to get me a picture of where the parts are located in the waverunner? If not its okay. Also if I have more questions I'll ask.

Thanks!

Man, I wish I had a picture for you. But ask if you need anything. You may also consider taking the boat in to be fixed if you are that unsure.

I'm in Tallahassee if you ever get there, I can do it for $40/hr...

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Hey,

It has been a long time since I have replied since I've been working on the Waverunner. It is NOT the carburator problem. Cleaned it out completely. I have been thinking about asking you to take a look. I live not far from Tallahassee. MAybe 3 and a half hours. Would you be able to finish in a day? Please reply. Thanks

Hey Howdy,

How are you?

So it's not the carbs, or you need me to take a look at them? I guess I'm not clear about your post. I'm here near Tally, feel free to give me a call. 850-997-4733,

Brian

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Hey,

Thanks for replying. What I'm saying, is if you could please take a look and see what the problem is and fix it.

Gimme a call.

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Brian,
Sorry that I didn't get back with you sooner.
We were out of town for the Labor Day long weekend and just got back last night.
I live in the panhandle area near Pensacola. It probably will take at least three hours driving to your place. I will keep your number handy and will give you a call when I don't have to work on one weekend.
Thank you so much for willing to take a look at it. I appreciate your time and willing to help.

C.K.

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