Does a 1988 150 black max have a overheating "safe mode"?

[saltfisher]

Previous owner never replaced the water pump/impeller for many years of him owning it. It needs to be done, and im not driving my boat anymore untill it is done. Last few times i had it out its limited for a few minutes at WOT only topping about 25-30mph then takes off, and at WOT it likes to back off the throttle by itself. Wanted to know it this motor has a "safe mode" it will run in if the motor overheats? When i was running the last 2 times the overheat alarm was on for a little while running WOT. Didnt know what that was untill comming here.

Thanks

 

[bgbass.1]

Re: Does a 1988 150 black max have a overheating "safe mode"?

yes there is a slow mode proably overheat problem

 

[gss036]

Re: Does a 1988 150 black max have a overheating "safe mode"?

You need to seriously think about a new water pump unless you want seize the engine so you buy a new one

 

[CharlieB]

Re: Does a 1988 150 black max have a overheating "safe mode"?

Injected Merc's will fatten the fuel 10% when a fault is registered.

Carbed models have NO protection other than the warning buzzer.

Change the impeller, check the rest of the pump carefully, a poor gasket can cause the pump to loose pressure at high RPM and overheat.

Wouldn't hurt to check the poppet valve, ensure the plunger moves freely, the diaphragm is in good shape.

How old are the T-stats, you can test them in a pan of water on the stove with a thermometer.

The more you check and verify the less the likelyhood of it failling on the water.

 

[j_martin]

Re: Does a 1988 150 black max have a overheating "safe mode"?

Most likely backing off at WOT is a fuel delivery problem. A combination of that (from neglecting the fuel pump, which should get a kit about once per year) and water pump (neglect again) very often causes piston damage. I'd check compression.

hope it helps
John