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-   -   350mpi overheating?? (https://www.offshoreonly.com/forums/general-boating-discussion/315131-350mpi-overheating.html)

1MOSES1 07-16-2014 12:27 AM

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.

mmr1229 07-16-2014 08:11 AM

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??

abmotorman 07-16-2014 04:46 PM


Originally Posted by mmr1229 (Post 4152259)
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.

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

commandersander 07-16-2014 08:24 PM


Originally Posted by mmr1229 (Post 4154026)
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??

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.....

Wobble 07-16-2014 08:31 PM

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


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