79 Mercruiser 5.7 log ex riser questions

I have two used risers for my brand new log style manifolds. Both are in excellent condition or I wouldn't consider using them. One has an insert where the water dumps into the exhaust, I suppose as a way to help prevent water backing up into the exhaust port. Also, the insert appears to be stainless steel. The other one I have does not have the insert. Does anyone know where I could get the correct info regarding which is recommended/best?

I have another question, does anyone know on a 1979 Mercruiser 5.7 which coil post the two brown wires from the starter belong? I am having some elec issues .......

Thanks in advance guys, your imput is greatly appreciated

Re: 79 Mercruiser 5.7 log ex riser questions

i have a 79,and i just replaced the mnflds. with center rise--these mnflds. have never been in salt water,and i got all records from day "1" !
my mnflds (at risers)have no insert in them !! ?
as far as your wiring goes --its this way
tan and yellow go to poss. +
black @ dist.,and brown go to neg - note the neg side is not hot until the ign. is rolled to start -then it becomes hot for start so it runs a straight 12 volts to dist.then once started the motor runs off the coil at a lower voltage(about 8)--
ifen,and whenen-you get a chanch pick up an hei dist. for your motor--1/3 the parts , and no points , no old style trap door for points--complete sealed unite

steven

Re: 79 Mercruiser 5.7 log ex riser questions

Looks like 2 different brands of risers.Different years??
They look good but used parts on new equipment is never a good idea.
Cobe Marine in Pasadena,Md.The parts guy is real good and might have the answer.J

Re: 79 Mercruiser 5.7 log ex riser questions

I have two used risers for my brand new log style manifolds.

Click to expand...

Ayuh,... Why would you wanta put used old mismatched risers on Brand New manifolds,..??