Problem With Outboard

[3inonegod]

I have a 1999 Skeeter with a 150 VMax engine. I is hard to start sometimes, mostly after it is warm. This fall had it out on the rock and it did something I can not figure out. Once it got running it ran great unless I went over 80% on the trottle. If I did this it would completely stahl or die. I ran it for hours at 75% throttle without an issue.

Thanks,

David

[motoman]

Sounds similar to a problem I had years ago. But, my old 1986 150 Evinrude is far more primitive than your VMax; although there may be a similar, common theme here.

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I started by changing the primer bulb, then the inline filters (I've got 2). This helped a bit, but then I changed the fuel pump diapharms...this helped a pinch more; but the problem was still there. Ultimately, I started looking at the fuel lines from the tank to the engine. I have the factory service manual I got off Ebay; and referenced it, and determined the previous owner (many, many years prior) had the wrong sized diameter fuel lines on. They were a pinch too small. Problem solved!

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All this to say; my thoughts lean towards fuel related. But, I always like to address anything that could be the culprit, that is cheap first; and also sound maintenance items. In my case, fuel primer bulb/filters had been in service for a while; so I went there first.

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Just thinking out loud here; but I'm sure sharper minds will step in and offer better advice!

[jmes]

I had similar problems with a 150 mercury I used to own, I ended up rebuilding the carbs and that fixed the problem

just my 2 cents

[Hillbilly Deluxe]

I had similar pronblem with my 1990 Johnson 150 GT. Tried the bulb, in-line fuel filter, and new fuel. Finally took it over to Premier Marine in Kimberling City. Rebuilt carbs and have not had any problems since. Cost was very reasonable.

[binman]

My tourney partners yamaha 200 did that and when he changed the plugs it fixed it temporarily. I told him too get it looked at he waited too long and lost compression on a cylinder and blew his motor up so be careful!!!

[Gary Lange]

If you want it fixed right then take it to HydroTec Performance Marine, on Enterprise in Nixa, Mo. Wayne and the boys are experts with the Yamaha Outboards and will get you going fast. Call Matt or Wayne at 417-725-5746.

[5bites]

If you want it fixed right then take it to HydroTec Performance Marine, on Enterprise in Nixa, Mo. Wayne and the boys are experts with the Yamaha Outboards and will get you going fast. Call Matt or Wayne at 417-725-5746.

This is great advice! Hydrotech are good folks to deal with.

I bet you will find that it's your fuel pump diaphragm/diaphragms.