OMC 5.7 King Cobra heat riser

[imported_Nathan_]

It's time to replace my heat riser on my 89 5.7 King OMC ... Any tips out there ? I've got 2 motors that I'm doing this to .. <br /><br />Nathan <br />Austin Tx

 

[rodbolt]

Re: OMC 5.7 King Cobra heat riser

hello<br /> yep<br /> DONT USE SILLI CONE<br /> I dont care how tempting it looks<br />just say no.<br /> use perfect seal but only if its a paper gasket. if it is the new style grey shiney teflon coated one use them dry but claen all old materiel from the manifolds followed by an alcohol or acetone wash to remove oils. I use the shaft mounted pads from 3-M to clean manifolds. sometimes a wire brush will gouge the surface. after cleaning use a medium mill file tomake sure the casting is flat. run a tapinto the holes and blow them out with air. good luck and keep posting.<br /> PS perfect seal on the exhaust hoses makes them slip on and seal.

 

[yoced]

Re: OMC 5.7 King Cobra heat riser

I agree with what rodbolt says here except that I would not suggest the use of the rotary discs. <br /><br />As with any tool, they can be wonderful in the hands of an expert. But, in the hands of an inexperienced user they can spell trouble.<br /><br />I have seen way too many 'over-prepped' manifolds where the gasket has nothing but a round face to mount to; leaks are bound to follow, with the user wondering why his brand new risers are failing.