No water flow

M

montana

Member
exMember
Joined
Apr 22, 2002
RO Number
8285
Messages
100
2002 4.3 Merc, Alpha 1 Gen 2, RWC

Initial start of the season. In driveway, running engine in muffs. Started engine, had normal water flow out of exhaust after a few seconds. Did watch temperature gauge slowly rise and then drop a bit as thermostat likely opened, as it normally would. Engine ran for a good 15 minutes or so. Then noticed temperature slowly rising, overtemp alarm went off. Temperature then dropped, alarm shut off. After a minute or so, temperature rose again until alarm went off. I then checked and no water was coming out of exhaust near top of drive. Water was just coming out from a round muffs. Shutdown engine.

I'm thinking to start with the impeller. But, I just had the impeller changed at the end of last season. After it was changed, the engine was run while prepping it to winterize. No problems at that time.

Any other thoughts?
 
How bad was the old impeller? was it missing pieces that may now be blocking water flow somewhere in the system.
 
Could have problem (kink) with the hose between the drive and transom. GenII impeller is more durable than alpha or earlier, but, it can go out earlier than expected.

Also check the thermostat housing. There are spring loaded 'balls' That can have problems with free movement from corrosion.

The thermostat itself can stick...even brand new ones.

Recommendation from Geo (GVP) was to drill holes in the thermostat. I drill two 3/16" holes in the diaphram (or cup), depending what kind you have.
 
The old impeller was 2 years old. I replace every 2 years as part of preventative maintenance. I didn't replace it myself, so I don't know its condition. (First year I didn't do it myself !!!)

I ran the engine yesterday again. Water flow normally out of exhaust. Engine stayed at normal operation temperatures. Ran for over 30 minutes, varying speeds. Perhaps I did have a problem with the muffs backing off on the initial day. But, I checked at that time and them seemed like they were on properly. Now I'm second guessing myself.

Even if the thermostat stuck, wouldn't I still have water flowing from exhaust?
 
I would change the impeller and try again.
 
Balls and thermostat both regulate water flow...an FYI to irregular gauge temp and/or overheating.

Water flow stoppage is strange. Could be from water hose flapped internally. Feel riser temps when flow stops. Is water getting to the risers or water flow interrupted earlier. Virtually the whole cooling system on an alpha has positive pressure so collapsing of hoses are unlikely...so unless the water hose between the drive and transom is kinked or maybe the water tube between the lower and upper case is loose or cracked, this problem has to everything taken apart and inspected.......Oh yeah, the flaps in the exhaust may stick some but not enuff to STOP water flow and still allow engine to run.
 
You must log in or register to reply here.
Back
Top