BF115 reverse flushwater relief valveoverheat shutdown

"Here,s another problem i had

"Here,s another problem i had today. Each trip brings another issue thinking of trading in...
After the sensor and fuel problems i thought i had it licked (wrong), Put the boat in at a river this morning, low tide, chewed a little mud getting too deep water, nothing to serious.
After about ten minates run the engine shut down and the overheat light was on, steam and all (not good).. Restarted the engine, had a good telltale flow, but the telltale water was very hot. Thinking there must be a problem with the thermostat i removed it and found it was fully open, as should be..Put it under the water and it closed as normal. refitted it and continued on for the day without any other problems..
It wasnt untill i got home and flushed the engine on the hose that i noticed that water was leaking from around the twin ports at the rear of the engine just below the rubber plug for the reverse flush. After removing the plastic couling i found that the reverse flush port or water relief valve as the seloc manual calls it was leaking.. Just wondering if this would be the cause of the overheating, thinking it must of had some crap get stuck in it or something like that too make it stick open.
My question is, is it possible too remove the valve all together and refit the cap itself with shorter bolts of course too prevent this from happening again.. Does the valve only act as a check valve for the reverse flush or does it act as a relief for the cooling system, cant see the need for it in that case.. I could of course just replace the valve but would rather eliminate the chance of the engine overheating again. Will removing the relief valve have any effect on the cooling system???? Or is it just there for the flush???"

"Which valve are you referring

"Which valve are you referring to?

The flush valve is the one under the cover that the 3/4 inch hose from the flush port is attached.

The relief valve is under the water jacket plate on the port side of the engine..a long narrow plate (about 3 inches wide...all the way down the side of the engine, directly below the thermostat).

Do not plug up the relief valve under the water jacket plate. If it is cracked or damaged, it should be replaced. You should probably replace the spring too, since it may be weakened. If it is open a little by debris or deformity, it could introduce hot exhaust into the cooling system near the thermostat. Theoretically, it could easitly cause an overheat.

I am surprised that your thermostat was not plugged up with sand or dirt after you chewed up the mud.


If you wanted to plug up the flush valve, that is probably ok....but, of course, it would make flushing difficult."

"Whew! If you're "chew

"Whew! If you're "chewing mud" to get that croc mate, I wouldn't be blaming the motor. If you do trade it in, you might want to shoot for a Jacuzzi pump instead of a prop."

"Mike in my previous post i wa

"Mike in my previous post i was refering too the flush valve, it was leaking when i ran the engine on the hose. A quick clean solved the leak, had a tiny bit of gravel on the seat.
I didnt know that the relief valve was in the water jacket...
After cleaning the flush valve i went out for a fish, the engine ran like a clock, a really sweat hum. But on the way home the note of the engine changed, bit hard too explain but the exhuast seemed to get a bit louder and there was a on and off hum.... This has happened the last couple of runs. Each time it has happened i have felt the tell tale water and it has been very hot too touch, havent actually measured the temp but it does seem too be up there, compared to if i idle it down for a for only a minute the temp of the tell tale is only luke warm.
Today i removed the water jacket covers and checked the relief valve and found three pieces of gravel on the relief valve rubber, each piece was about 1mm round... I cleaned out the jacket and valve and reassembled.. Will test drive tommorrow...
Do you know what the temperature of the tell tale should be round about, I am thinking that my engine must be close too overheating, it is hot too touch, wondering if the engine is staring to derate even though there is no overheat alarm sounding...Only heats up like that after siting on 4 to 5000 rpm and after 30 too 40 minutes run time..Hopeing i dont have a cracked head but i think it would play up before running for this long so wont go there just yet.. Have done a comp test and all pots are around 190 too 195 psi but the eng was not as hot as it could have been...
My main concern is the change of note of the engine and the temperature of the tell tale... Any thoughts would be really appreciated...."

Forgot too mention that when t

Forgot too mention that when the note of the engine changes it also seems too loose about 400 rpm

The thermostat starts to open

The thermostat starts to open at 72 deg C and should be fully open at 82 deg C. That is pretty warm.

I can not explain the change in tone or the rpm reduction. It could be just as you are theorizing...beginning to overheat...

Have you changed your impeller recently? It could be getting weak or worn.

"As I just sent this post, I r

"As I just sent this post, I remembered that you went through mud. Mud or sand can cause scoring inside the waterpump housing and plate. Your water pump could be severely impaired."

Aussie Grunta, Launched at shady at low tide?

I have ahonda 50. I find the water coming out the pee hole is pretty hot too after a bit of a run, esp when the water temp is already up around 32c.

So dont worry too much, mine is hot enough that I feel almost burnt sticking my fingers in, but it is not really much more than 75c,

After the mud run, you may need to pull the thermo again and put a hose in and blast some gunk out, it seems to hold up in the waterjacket a little, but really for my, if there is a good flow, hot water isnt too bad.

As for the change of sound, it is probably just the warm water letting things open up. Mine makes all sorts of weird noises at various parts of the trip, and I used to worry about it, but in the end its just a motor making noises that always change. As long as mine doesnt go bang, I keep going. I do lots of long runs in remote places and the things it does are pretty funny and if let them all worry me, I wouldnt go anywhere... I have an epirb and a broke motor probably wont sink me..

Regards

Chris