2003 Merc 150 2 stroke runs hot

[coach_jesse]

I'm looking at buying an old Mako with a 2003 2-stroke Mercury Saltwater series 150HP V-6. It's not an Optimax but the entry level 2-stroke. I am nervous to buy because the water coming out the engine is very hot to touch. Almost scolding. Owner says he replaced impeller and it is normal for a V-6 2 stroke Merc to run at that temp. Anyone else have a V-6 2 stoke Merc? Do they really run that hot?? Also the water wasn't streaming out very fast at low rpms. I saw another post about replacing a Poppet valve. I am also thinking may need a new water pump? Any clews or experience with this motor? Thanks

 

[timmathis]

Re: 2003 Merc 150 2 stroke runs hot

I have seen some get pretty hot to touch.<br />It should have a overheat alarm horn and the stream should pick up with rpm's. When did he replace the impeller? It should be done every year in salt! Tim

 

[coach_jesse]

Re: 2003 Merc 150 2 stroke runs hot

 

[coach_jesse]

Re: 2003 Merc 150 2 stroke runs hot

It was replaced last summer and only used a few times since. I looked back at many forums and found one stating that in Merc's the water runs through the block before exiting. Therefore is very hot to touch. My Yamaha 4 stroke hardly even gets warm. I assume it is because it doesn't run through the block. I'm starting to feel more comfortable with the hot water out the telltale on the Merc. 150. The alarm didn't go off. But I also didn't notice it when the motor was started.

 

[gss036]

Re: 2003 Merc 150 2 stroke runs hot

It should have water discharge at about 143 degrees. Low flow at idle and the it picks up. The engine water pressure at idle is probably about 2 # and 12# at 5000 rpm. It should take a couple of minutes for water flow depending on outside temperature at the time. I think you are ok with the impeller.

 

[timmathis]

Re: 2003 Merc 150 2 stroke runs hot

It looks like you will be O.K. Jessie.<br />Good Luck and welcome to iboats, Tim

 

[coach_jesse]

Re: 2003 Merc 150 2 stroke runs hot

Thanks for the replies. As soon as I felt safe about the telltale temp. My mechanic returned my call and recomended not getting a Merc 2 stroke. He didn't say exactly why but he made them sound undependable in salty tropical waters with high corosion. I respect him as a mechanic. He's always been honest and done good work on my Yamaha. But he also doesn't work on Merc's. He stated that he didn't know any Merc mechanics that he would recomend here on Oahu. This list is probably bias towards Merc's but I guess I'm looking for some opinions either way. I'm looking at a 1976 Mako in good cond. with 2003 V-6 150 Saltwater 2 stroke with trailor for $8,000. The boat rode well doing 30 @ 3500 and almost 45 at WOT around 5400 or so. Motor seemed in perfect cond. Boats for sale like this locally are not too common. Besides hot telltale which seemed norm. I could hold my hand there for about 3-5 seconds with out getting scorched. Any one know any good Merc mechanics in Oahu?