454 bravo 1 overheating...really stumped! :-(
 

boat is a 1989 formula 272

twin 454 with bravos

i am goign to do my best to describe whats its doing and what ive done...i really just don't get it...i need help...ive tried researching threads but i don't see one that fits my issue

ok 2 weeks ago circulator pump went on the starboard motor...was running a little hot about 175...figured changing the pump would fix this issue...nope

so i look into the oil cooler...i changed it out it looked rusty...didn't fix it....so i looked to the circulator pump...i changed the impeller as well as the gaskets and the stainless plate...no change...still running hot...i open the thermostat housing...find no thermostat...(i tried running without it and with a 140 that i bought...no difference) here is what i get temp wise

at idle temp 165

at 2800 temp 170

at 3000 temp 180

at 3200 temp 200

bring it down to 2600 and it drops to about 175-180

in nuetral at the dock i can bring it to 3000 and it wont heat up which is so strange but maybe i am not giving it enought time too.

what do you guys think i should do i tried backflushing all the lines from the seawater pump out the drive seemed ok and flushed all lines. i am on the south shore of long island where its very shallow and sandy and we anchor out on the sandbars alot...

boat is in a slip...and i have no trailer so it will be costly to pull and look at the drive...but upon inspection underwater it looks good

sorry its so long

i am new to bravos and would love to find out what to do next...it seems like a simple system i cant figure out why im having trouble

the plastic insert that holds the hose into the transom assembly and the helmet are probably corroded and closing off the hose

the plastic insert towards the back that the hose to the seawater pump goes to? when i disconnect this hose water comes rushing in...this is so frustrating...seems like the flow is great

fixx
 

+1 or the plastic doo hicky in the drive that holds the brass tube going to the wate impeller pump is leaking water back through the prop..start boat up on the hose,start the enginethat not giving you trouble snf notice how much if any water is coming out from the center of the prop..now do the same to the troubled engine and see if its the same amount or more..if more then you have a internal leak or the oring slipped where the drive bolte on and is dunping the water into the exhaust passage of the drive..

It sounds like you've been as thorough as you can troubleshooting the water coolant system. Maybe you should consider your Oil Pump. They Often go from Fine to Broken but occasionally, though rare, they do get tired and pickups become clogged with Varnish and other nasty engine deposits burned off but not completely away. My guess is with the screen plugging up or your pump wearing out, the decrease in Oil pressure wouldn't be Noticeable at the Higher RPMs, but I bet it's 5 to 10 lbs lower after a hard run than it used to be. Just a thought. I'll cross my fingers that it's your thru hull bottleneck and not your oil pump.

Where are you getting the temp reading from - the guages??

yes on the gauges...risers are also hotter to the touch than the port motor
...looks like i will have to have the marina pull the boat! so i can get a hose on it...and really check it out

oil temp is 40 at idle than 50 at cruise...its about 20-25 after a hard run than creeps back up to 35-40 after a few minutes

Pull the boat and pull the drive off, temps will be fine on the hose even if partially clogged

what am i looking for tho if i pull the drives off...bravos are new to me

On the transom is a plastic fitting that the water hose attaches to. It is held by 2 small bolts. If you remove that (a b!tch on most boats) you will see the rubber feed hose behind it with a small plastic insert that holds it in place. What we suspect is that the hose has corrosion between it and the transom and it has collapsed the hose and insert. Very common on older Bravo boats.