1997 mercruiser mag mpi water temp 125-180 fluctuates

[272Baja Jeff]

My 1997 mercruiser mag mpi serial number OK 151402 water temp is up an down al the time.Replaced thermostat sending unit an water pressure sensor.I have a Hardin Marine stainless steel housing on my sea water pump. My 454 also has the stainless marine exhaust with stainless marine crossover an Hardin Marine thermostat housing gauge seems to be pretty close cause when temp is up where it should be boat run 4800 rpm an 62 mph.but when cool the ecm seem to go to a guardian mode only running 4200 rpm an 57 mph.Any help would be very much appreciated.

 

[tpenfield]

There is a plastic insert within the thermostat housing. Make sure that has not spun around from its normal position. There should be a notch that holds it in place.

 

[alldodge]

has the stainless marine exhaust with stainless marine crossover an Hardin Marine thermostat housing

Can you post a pic of your setup?

 

[Bondo]

My 454 also has the stainless marine exhaust with stainless marine crossover an Hardin Marine thermostat housing

Ayuh,..... Welcome Aboard,..... You've got Nothin' Mercruiser there,....

Like AD says, post up some pictures of yer set-up,....

 

[272Baja Jeff]

Tired to load pics but it said to big how do I resize them?

 

[tpenfield]

Tired to load pics but it said to big how do I resize them?

With a Mac (OS X) you can resize using the Preview App. With Windows, you can resize with Paint App

You are trying to get the photo to be 200KB or less

 

[Bondo]

Ayuh,.... I use Picasa to resize to 480 x 640, 'n export 'em to photobucket, then link 'em into my posts,

.....