94 MERC 150 BM PUMPS WATER FOR 5 MINUTES THEN OVERHEATS

[dennis1]

i JUST BOUGHT A 150 MERCURY BKACK MAX '94. AT FIRST IT WOULDNT SUCK OP ANY WATER AT ALL AND OH AFTER ABOUT A MINUTE OR THREE, SO i REPLACED THE IMPELLER AND IT SEEMED TO WORK FINE. i PUT IT IN THE WATER AND IT WOULD RUN FINE FOR 10 OR 15 MINUTES AT A TIME THEN THE WATER WOULD STOP COMING OUT OF THE TELLTALE AND THE ALARM WOULD GO OFF. iVE DROPPED THE LU ABOUT 10 TIMES TO CHECK MY WORK AND IM STUMPED. aLSO LAST TIME i STARTED IT THE OIL ALARM WENT OFF ALSO EVEN THOGH THE RES IS 1\3 FULL.cOULD THIS BE A BLOWN HEAD GASKET? OR THERMOSTATS , WHICH ARE NEW? WHAT COULD THIS COST?

 

[gss036]

Re: 94 MERC 150 BM PUMPS WATER FOR 5 MINUTES THEN OVERHEATS

One thing at a time. Please no caps, that is shouting!! You say the res is 1/3 full, if that is the onboard (tank under cowling), then add more oil, it is telling you it low and there is only about 20 minutes of run time left. The overheat issue could be your poppet valve sticking open or bad diaphram letting all of the water go out through the exhaust. Do you have a water pressure guage? Start w/ the poppet and see what happens.

 

[Perfidiajoe]

Re: 94 MERC 150 BM PUMPS WATER FOR 5 MINUTES THEN OVERHEATS

Check the thermostats, if it overheats, or starts to after 10 minutes of low speed operation. Good Luck, Joe

 

[dennis1]

Re: 94 MERC 150 BM PUMPS WATER FOR 5 MINUTES THEN OVERHEATS

THE REMOTE RES is 1/3 full the onboard is full.Where and what is the poppet?Ireally appreciate the advice, guys.

 

[KCLOST]

Re: 94 MERC 150 BM PUMPS WATER FOR 5 MINUTES THEN OVERHEATS

When you say alarm at overheat, I assume you mean a constant beeeeeeeeeeep! Is that correct?<br /><br />If so I would definitely check (or even replace) the t-stats, poppet valve assembly...<br /><br />The stats are located on the top of each cylinder head.. Hoses are attached to each just above the top spark plugs... The poppet valve is located on the starboard bank, down low, below the switchboxes...<br /><br />Let us know....