raw water pump belt slips ??
 

I put my boat in the water for the first time sunday and not even a 1/4 mile offshore and the belt for the water pump was tore up, it jumped to a different grove on the crank, after I put it back we had to idle in or it would slip on the pump pully.

Re: raw water pump belt slips ??
 

Forgot / I tried a size smaller belt and the crank pully was tuching the raw water pully. My belt size it seems the bracket will not adjust out far enough to make real tight. Not sure if pully is to large on the raw water pump. P.S. the boat is new to me and as a trail of FU**ed up parts.... You can see pump in photo some what..

Re: raw water pump belt slips ??
 

My raw water pump has it's own belt - the belt only goes from the crank pulley to the pump pulley.
Is it possible that something is wrong with your setup?

Re: raw water pump belt slips ??
 

Yep I agree with Tinkerer. You do not have enough of a wrap on the drive pulley on crank. Even if everything is lined up and straight I believe you will always have trouble with slippage. I do not see power steering or alternator set up in the picture.
My raw water pump pulley is much smaller that what you have pictured and is a short belt but I do not run a water circulating pump.

Re: raw water pump belt slips ??
 

I agree with the rest...definitely not enough contact area on the crank. Mine too , had its own belt that rode in the center groove on the 3 belt crank pulley.

Re: raw water pump belt slips ??
 

Here is a photo with the outher acc on the engine. Heres how it runs the water pump pully runs the power stering and the alternator / inter grove is alternator - middle is raw and crank - outer is power steering, at the crank the grove used is the inter grove and that runs the the water pump back down to the raw water pump. Thats the only grove thats line up with the cir pump pully. I might need some new pullys

Re: raw water pump belt slips ??
 

I just went through a pulley exercise this winter, couldn't keep my alt/crank/circ pump belts on, leading to cracked heads, holes in a piston, other ugly-ness. I agree with the others here, not enough wrap on the raw water pump pulley.

Here's some pics of before and after. One word of advise, go to a "17" series belt, as Merc belts are "15" series, and pretty whimpy. The "17's" fill the pulley grove nicely, and are much beefier. Napa was pretty good about helping me through the fitting process.

I have a stack of Merc blue pulleys, so if you need something let me know.

Before...

Re: raw water pump belt slips ??
 

after...

Re: raw water pump belt slips ??
 

I bought a new crank pulley last night, it has two groves that line up with the water pump pulley. So I will run the raw water by it's self and the crank-alt-circ, and the power steering will run to the circ pump. I will see if this will work better.