350mpi overheating??
 

noticed that my starbored engine 350mpi bravo 1 drive was heating upto 175degrees alot faster than my port engine. however after cruising for about 10-15min the port engine eventually catches upto the other?? i thought maybe i had sucked up some debris in that drive but flushed both units several times and it still seems to heat up alot fater than the other. not sure what to do next, disconnect engine hoses and check for additional debris?? i did churn up some sand a few weekends ago but had a 40min ride home afterwards i would have thought it would have cleaned most of it out?? not sure any thoughts??

It could be that the engine that's taking longer to heat up has a thermostat that is stuck slightly open.

interesting, so for the motor to warm up to 175 degrees in about 5 min is no problem? and is 175 too warm?

additionally, when i flushed both systems they both seemed identical in terms of water flow.

bravoitis... first place to ck is the feed hose at the transom ..save alot of time and ck that first .then move on to sea pump ect

i apologize but can you elaborate... i assume you're speaking of the hose that connects from the water pump to the transom assembly??

sounds like this is a common problem with the bravo drives??

yes it is extremly common ..it doesnt have to be a salt water boat either ..ive fixed so many i cant count em .i make it common practice to ck them every time im working on a transom or have an engine out

ouch! so... i have to pull the motor? im new to the performance boat set up, sorry.

motor dont have to come out to ck it. 2 bolts hold the adapter on that the hose connects too at transom .you will need 7/16 wrench.. under that adapter you should be able to stick your finger in the hose thats there ..corrosion builds up around the outside of the hose and shrinks it down to nothing ..ive seen more guys remove thermostats replace impellers and circ pumps only to find its the supply hose that wont pass water

thanks so much... will definitely check it out.

Are you flushing them using installed flush outs or using muffs? If you are using muffs and are still getting good flow then the pick up tube is not your problem.

i wasnt aware of the bravo 1 hose issue myself...might be worth checking out.

if that checks out ok, youll want to check the raw water impellar. when is the last time it was changed? maybe a sticky thermostat but if it fully opens after a bit of running, its likely ok. if you say you picked up some sand...might want to pull the raw water plugs and see if any debris drops out. could be possible that there is debris within the drive itself too. keep us posted with updates.

yes muffs and that was what I was thinking. both motors/drives had adequate water flow when flushing with the muffs and actually both exhaust water temps felt very similar in temp. there was no noticeable difference in the feel of the water from each motor.

I think my next plan of action will be to run the boat and take some temp readings with an infrared temp gun on each head to be certain its not my gauges?? if they differ I would assume its the t sat?

suggestions/thoughts??

On the attached video you will see I had a thermostat that wasn't closing properly. Both engines would run exactly the same temp under load but Port took forever to get warm. Not saying this is your problem but for $3.99 at Ol'Reilly i would change it out to see what happens.

Look at 3 min then 4 min mark.

https://www.youtube.com/watch?v=zRUD-M1SI0s&list=UUfTaZ1E35kPJcDCgmYx_l2A

Sorry to say....but don't assume anything...especially with a boat.

You have the answer in the quote above.

On muffs, you are forcing water through with a garden hose....about 30 psi.....so at that point, you need no impeller....or tstat....or circ pump.....

In the water, the impeller in the raw water pump acts as a lift pump to feed the circ pump to feed the cooling passages attached to the output mated to the block, manifolds, heat exchangers and exhaust. Without sufficient "lift" (raw water impeller) you will see a significant rise much faster in a damaged/lame impeller faster that one that operates as designed.

Consider this:

Bias ply tire sitting overnight in the cold. In the morning, you drive a 4-flat spotted vehicle until the heat of driving relaxes the "memory" of the tire.

Impellers have this same memory. The impeller housing is round, but off center.....meaning.....when not in use, several fins are relaxed, and several are strained due to the compression on the short side of the pressure cyclone (or cycle.....pick your own nomenclature).

Essentially, the impeller retains the memory of simply sitting In one position for any period of time....however,the length of the "sitting" haS a much bigger effect. So.....

Remove the raw water impeller. If the fins remain "bent"....it's bad. Broken impellers are a sign of lack of service. Bent ones are an indication of lack of use.....

I'd say throw in two new t-stats and see what you have, 175 running temp is fine as long as it stays there