I developed a vibration in my outboard last week, very slight but noticeable. At first glance I thought it was the prop. Now it looks like the prop is running out just a little. I pulled it off and checked the prop shaft at the spline total indicator movement was right at .006". Does anyone know what it should be? Also, one of the blades on the prop had a small dent in it. What is the redline of these outboards? around 5100 rpms seemed to be the max I could get out of it.How hard is it for your average mechanically inclined guy to change? Or is this one for the mechanic only? Any help greatly appreciated.

Oh yes, I forgot to mention, its a 1999 Yamaha Vmax EFI 200HP.

From what your saying about only turning 5100 rpm, it sounds like you have lost some power. Should turn 5800 rpm. I would change the manual fuel pump diaphrams, as anytime your down on power or running ruff thats where you go first on a Yamy. Do`nt think .006 is enough to vibrate but it could be the prop and a good prop shop can check it. GOOD LUCK

Thanks Gary, I'm not familier with these engines as this is my first Yamaha, where are these diaphrams located? Are they pretty easy to swap out?

This might be a strech, but I had a vibration in my motor, althow I wasn't going full throdle, ended up be a broken pinion gear.

I don't think it is a pinion gear. I took it out this weekend after I straightend the dent out of the prop blade. I didn't really notice a vibration. However, it started losing power right at 5k rpms. I'm wondering if it could be related to ethenol gas I may have picked up without knowing? Or if there is a clogged fuel filter. It was almost like it was running out of fuel or air or both? Advice?

You are definately down on power. I would run a compression check and then a leak down check before anything. If that checked out mine would be off to the shop for the fuel check. They have the equipment to pinpoint the problem without you pulling your hair out.

Good luck.

Bassman, Leak down check? Are you thinking the fuel bulb is not holding? Is there a check valve to keep the fuel from draining off?
Man, I hate not having a service manual for this thing. I ordered it and hope it gets here before this weekend. Is there a technical website that has details about Yamaha engines?

This serves me right for running the H out of it putting it up wet and not doing proper interval maintenence.....working all the time and fishing every chance I get...has been a great engine so far knock on wood! hope its a minor fix not compression issue...is there a proper psi it should hold per cylinder? thanks

Leak down check to see if the cylinder will hold pressure. This will tell you if you have a ring problem.

Bassman,
I ran a compression check last night I think I'm in good shape there were all within 5 lbs of each other. I talked to another guy that steered me toward the fuel pump filter and I cleaned it.
Took it to the lake and didn't have a distinct power loss on top end. I was able to hold it around 5700 for a few miles. I did notice the tach drop off one time but I didn't feel it as before.
I am going to order a new fuel pump filter and a diaphram kit for the pumps. I have dropped off a few MPH at top end but it still ran 65 all out,then it started getting a little squirrely.
I'm wondering now if the jackplate is set right? this boat will porpose and bob like crazy at around 20-30 MPH. You have to throttle it pretty hard to get it to stop....Does anyone know the correct height with the engine trimmed all the way down? It is a 1999 Yamaha 200 1999 Skeeter ZX195C