4.3 riser cooling problems HELP

[z284u2try]

4.3 mercruiser 1998 18.5 bayliner alpha 1

I put a new engine water pump and 160 stat on this past weekend. Reason for this was the weep hole on the pump was leaking. The impeller is around 1 year old.

My driverside riser is getting hot but still be able to keep my hand on it. and my passenger side riser is staying very cool. I am guessing its time for new risers? I put the water hose on the hot riser water inlet and it flowed well is this normal?

I notice that this is a one piece riser and really don't see many of these.

My boat runs at 175 on the muffs with a 160 stat i think this is a bit high. Will it run even hotter under water load?

 

[Bondo]

Re: 4.3 riser cooling problems HELP

My driverside riser is getting hot but still be able to keep my hand on it. and my passenger side riser is staying very cool.

Ayuh,....
It's quite Normal for 1 side to run warmer than the other......

 

[z284u2try]

Re: 4.3 riser cooling problems HELP

Its hot like hell HOT. Uncomfortable to hold your hand on it. The other side is very cool like room temp. I will take your word for it.

 

[Bondo]

Re: 4.3 riser cooling problems HELP

Its hot like hell HOT. Uncomfortable to hold your hand on it.

Ayuh,......

Just the Fact that you Can put your hand On it tells Me,...
That it's probably Well Under 200?.........

 

[brianvolt7]

Re: 4.3 riser cooling problems HELP

I had a similar problem with a Bluewater that had a 4.3. At idle it would heat up and when revved it cooled down. Boat shop told me to install a new impeller though I had just done it about two months before. I ended up taking their advice and it worked.

 

[z284u2try]

Re: 4.3 riser cooling problems HELP

Ayuh it must be under 200.
Maybe I will try a new impeller first.
Thanks for the help guys.