4.3l Possible Overheating Question

[tahoejag]

Recently noticed starboard riser VERY HOT, port side cool. Running under normal conditions, normal temp reading (aprx 175-fairly new thermo and impeller). Check balls are free and seems to have water running thru and into both risers. On the mufffs, noticed water from y pipe on port side of transom is warm (the side the riser is cool), while water on starboard side of y pipe is cool (the side the riser is very hot). With engine off now, unhooked hoses from t-stat housing where check balls and ran hose water thru them to the manifolds. Had even water flow thru y pipe on both port and starboard sides. It is a raw water cooling system. Normal temp reading on gauge. Can't figure this out....Maybe clogged riser?? Riser is VERY HOT, could it have damaged anything being this hot and running boat?

2006 4.3l carb TKS
180 degree t-stat

 

[Don S]

Re: 4.3l Possible Overheating Question

Could be a plugged manifold or riser. Do you boat in salt water? When was the impeller replaced last? Why do you have a 180? thermostat, 160? is what should be in it.

What is the serial number for your engine, 2006 doesn't help.

 

[tahoejag]

Re: 4.3l Possible Overheating Question

Don S....I boat in fresh water (Lake Huron), the impeller was replaced last season, which didnt even need it, but replaced it anyway while it was apart. I replaced the t-stat beginning of this season with 180 (which merc dealer stated that was the correct temp being carbureated, that merc wants to run carbbed hotter than MPI) I questioned that myself....he stated lower temp t-stat (160) is for MPI 4.3's. Sorry don't hav ser # handy. Hope this info helps.....

 

[tahoejag]

Re: 4.3l Possible Overheating Question

Don S....My total bad! 160 IS the correct tstat i have installed....dealer mentioned 140 degree for MPI's. Again...sorry!!!

 

[Don S]

Re: 4.3l Possible Overheating Question

Is this happening in the water? or on the muffs? If on the muffs, it's probably fairly normal depending on the amount of water volume you have on your garden hose. Do you have an Alpha outdrive?

 

[tahoejag]

Re: 4.3l Possible Overheating Question

Is this happening in the water? or on the muffs? If on the muffs, it's probably fairly normal depending on the amount of water volume you have on your garden hose. Do you have an Alpha outdrive?

This is happening while boating (the temp diff in risers). I notice the water temp diff from y pipe on the muffs. It is a apha i gen II drive.