So I've had an on/off issue with my bought new 2018 Boat Motor. Quick Summary - I believe at WOT I'm getting cavitation that is getting sucked into the water pump intake.
I'm Leaving out a lot of test/details/chatter to make this easier to read and understand .... So please work with me here ...
Details, With My Phone Vessel View app /motor connection - 2018 Merc 4s 60hp CT Engine Starts and gets to 120F and holds steady at idol. I can drive it at any speed UP TO 3/4+ throttle and temps hold at around 140f. Short / longer run times same. This is how I drive 99% of the time.
When I get it to WOT 5k+ RPM and Trim up to get best speed - the Temp climbs to Overheat (OH). If I Full tilt down (in) and run WOT it's better, RPM drops a tad due to bow down, to just over 5K and it runs fine at 140f - EXCEPT when I TURN ! left then it climbs to OH.
IT did this 2nd year I had it (not often I do an extended WOT run). And I rarely have the temp / phone app in the boat to monitor ,temp. And I do have cavitation burns on my prop. Fresh water only, Motor has been well flushed.
So I'm thinking the following possibilities....
Thermostat is 2? years old and I think is OK.
Water impeller is 4? years old and due for a change but I think it's fine ...
Motor's cavitation plate /motor mount height SEEMS to be in correct position height wise - but the engine might go down a little (one hole) - depending on how the holes line up - I might have to re drill if I'm off on the hole pattern. (but even with tilt full in and when turning I get higher temps ).
I Doubt I'm sucking air (Ventilation) in at the prop at WOT as the Tilt is all the way in - but slightly possible.
I'm thinking that I'm getting cavitation (Water boiling at low pressure at the prop) that may be causing it swirl around the prop and water intake hole and preventing the water from flowing close to the intake holes???
It's said that 4 blade prop instead of 3 blade prevents some cavitation. For About $230 I can get a 4 blade (cross ref to the best prop from my 3 blade 11 pitch).
Thoughts?? Thanks
I'm Leaving out a lot of test/details/chatter to make this easier to read and understand .... So please work with me here ...
Details, With My Phone Vessel View app /motor connection - 2018 Merc 4s 60hp CT Engine Starts and gets to 120F and holds steady at idol. I can drive it at any speed UP TO 3/4+ throttle and temps hold at around 140f. Short / longer run times same. This is how I drive 99% of the time.
When I get it to WOT 5k+ RPM and Trim up to get best speed - the Temp climbs to Overheat (OH). If I Full tilt down (in) and run WOT it's better, RPM drops a tad due to bow down, to just over 5K and it runs fine at 140f - EXCEPT when I TURN ! left then it climbs to OH.
IT did this 2nd year I had it (not often I do an extended WOT run). And I rarely have the temp / phone app in the boat to monitor ,temp. And I do have cavitation burns on my prop. Fresh water only, Motor has been well flushed.
So I'm thinking the following possibilities....
Thermostat is 2? years old and I think is OK.
Water impeller is 4? years old and due for a change but I think it's fine ...
Motor's cavitation plate /motor mount height SEEMS to be in correct position height wise - but the engine might go down a little (one hole) - depending on how the holes line up - I might have to re drill if I'm off on the hole pattern. (but even with tilt full in and when turning I get higher temps ).
I Doubt I'm sucking air (Ventilation) in at the prop at WOT as the Tilt is all the way in - but slightly possible.
I'm thinking that I'm getting cavitation (Water boiling at low pressure at the prop) that may be causing it swirl around the prop and water intake hole and preventing the water from flowing close to the intake holes???
It's said that 4 blade prop instead of 3 blade prevents some cavitation. For About $230 I can get a 4 blade (cross ref to the best prop from my 3 blade 11 pitch).
Thoughts?? Thanks
