Overheating 50HP year 2000 4 stroke efi

[Wayne Martin]

Hello All.

I have a new boat and am having overheating problems.

It's a 2000 Suzuki 50 four stroke with EFI.

After running anywhere above 3500 rpm's in the water for about 10 minutes, my overheat alarm goes off and the motor retards itself to under 3000 rpm's. I will run it at idle for a few minutes and it will cool off and the alarm will quit.

This will happen only when its in the water and has a load on the prop. I can't get it to overheat at any rpm on the hard, with a muff on. It has to be in the water.

It does and always pees strong.

I have replaced the temp sensors, thermostat, and the impeller (with new plate and gasket).

I have flushed the crap out of it with Salt Away. And I have back flushed it. All seems to be free of blockages and all holes everywhere drains out fine.

Not really sure what to do next. The technicians are reluctant to work on something they can't duplicate in the shop.

I do have a very small groove on the housing side of the impeller housing. Could that matter?

What else can I do to repair or trouble shoot?

I am tired of not getting this up to speed....


I will also do some searching on this forum for additional info.

Thanks in advance.

[artdf175]

I don't know your specific engine
do you have the repair manual?
you might check to see if this model has a pressure relief valve?
thete has been discussion relating to this not working
as with the impeller housing, seems like anything that prevents full pressure to the system has been a problem
also when you put the lower unit back together there has been gasket fit problems on a number of cases
another thing to try would be running without the thermostat just to rule out a possible defective thermostat
Art

[Wayne Martin]

Ok. Thanks Art. I ordered a new housing today. We will see if that does the trick.

[pniksnut]

problem solved ??

[artdf175]

The likelihood of having this guy respond is minimal
start a new thread and give us your details
Art