Merc 150 EFI Black Max - Steady Alarm

[imported_Jerry]

Had boat out this morning and continuous alarm went off. Motor died, but re-started and I could creep back to the boat ramp in idle speed only. At ramp, motor turned over real easy when out of the water. Soon as put in the water, would cut off. Water continued to stream out the back all along, so there was no stoppage of water. Any suggestions? Thanks.

 

[imported_Jerry]

Re: Merc 150 EFI Black Max - Steady Alarm

Had boat out this morning and continuous alarm went off. Motor died, but re-started and I could creep back to the boat ramp in idle speed only. At ramp, motor turned over real easy when out of the water. Soon as put in the water, would cut off. Water continued to stream out the back all along, so there was no stoppage of water. Any suggestions? Thanks.

Forgot to mention year of motor is 2001.

 

[imported_Jerry]

Re: Merc 150 EFI Black Max - Steady Alarm

Help, new lady boater here. Afraid to take it in to the shop un-informed. Don't want to get burned. Thanks again for any help you all can give.

 

[phatmanmike]

Re: Merc 150 EFI Black Max - Steady Alarm

usually steady alarm means overheat. there is a nother post this same topic just above this one.

http://www.iboats.com/bbboard/bbBoard.cgi?a=viewthread;fid=29;gtid=1120771

 

[andy6374]

Re: Merc 150 EFI Black Max - Steady Alarm

The continuous alarm is the overheat alarm. Did the overheat occur at all RPMs? It could be 1 of 3 things or a combination of...the waterpump, tstats, or the pressure relief valve.

When the last time you had the waterpump changed out? tstats?

 

[imported_Jerry]

Re: Merc 150 EFI Black Max - Steady Alarm

usually steady alarm means overheat. there is a nother post this same topic just above this one.

http://www.iboats.com/bbboard/bbBoard.cgi?a=viewthread;fid=29;gtid=1120771

Thanks for replying. Have been reading that thread. Thanks again, really appreciate the response.

 

[imported_Jerry]

Re: Merc 150 EFI Black Max - Steady Alarm

The continuous alarm is the overheat alarm. Did the overheat occur at all RPMs? It could be 1 of 3 things or a combination of...the waterpump, tstats, or the pressure relief valve.

When the last time you had the waterpump changed out? tstats?

 

[imported_Jerry]

Re: Merc 150 EFI Black Max - Steady Alarm

The continuous alarm is the overheat alarm. Did the overheat occur at all RPMs? It could be 1 of 3 things or a combination of...the waterpump, tstats, or the pressure relief valve.

When the last time you had the waterpump changed out? tstats?

Just got the boat - no maintenance record, but was supposedly tuned up about 2 months ago. Overheat occured during faster RPMs. Was able to get back to the dock in idle speed. Once at the boat ramp, motor would run at higher RPMs, but would "sound the alarm" when fully immersed in the water.

Thanks for your reply and help.

 

[andy6374]

Re: Merc 150 EFI Black Max - Steady Alarm

An overheat at higher RMPs is indicative of a poppet valve not opening or a waterpump that cant keep up (either the impeller is spun on its hub or the vanes are damaged). Check out the poppet to see if any debris is clogged in the spring causing the poppet not to open.

 

[imported_Jerry]

Re: Merc 150 EFI Black Max - Steady Alarm

An overheat at higher RMPs is indicative of a poppet valve not opening or a waterpump that cant keep up (either the impeller is spun on its hub or the vanes are damaged). Check out the poppet to see if any debris is clogged in the spring causing the poppet not to open.

Just got back from the boat shop. They say the impeller went out, which caused the #5 cylinder to burn out and that it will take $1500 to $2000 to repair (parts and labor). Does this sound right?

 

[andy6374]

Re: Merc 150 EFI Black Max - Steady Alarm

The price sounds about right to me, but not the cause. If the waterpump bit the dust then all cylinders should have burnt out or damaged...especially 1 &2. Sounds more like a clogged/dirty jet.

Whats the condition of the other cylinders and pistons? Did they measure them too?

 

[imported_Jerry]

Re: Merc 150 EFI Black Max - Steady Alarm

The other 5 measured around 127 lbs. of compression. They are going to try to clean up the one that was burnt out if able to, or re-sleeve it. They are going to change out the power head, put in a new impeller, check out all of the electrical, re-lube and tune-up. They say this will make the motor run like new. They told me that I should change the impeller once a year and have the engine serviced to keep it running like new. They will do that for about $70 labor plus around $35 for parts, so once this big repair is done, that sounds like the best thing for me to do each year. Does this sound right? Thanks again for all your help.

 

[andy6374]

Re: Merc 150 EFI Black Max - Steady Alarm

You are getting a different powerhead? I thought you said they were just going to re-sleeve the bad cylinder.

Once again, I think the reason for failure is more likely a clogged jet rather than the waterpump. I mean the waterpump could have been the hump that broke the camel's back. But one cylinder failing when the others are fine is surely a dirty carb. Have them inspect the carbs and make sure then clean them (which is part of any rebuild). Some of the older black max's ran lean and larger main jets were installed. Probably your problem.

I suggest a installing all new pressure relief valve components, new tstats, and a fuel pump rebuild while you are at it.

Remember with carb'd engines...if the carbs are clean and the cooling system is up to par then the engine will run forever!