2GM20F Engine overheating
- Thread starter admorton
- Start date
So if I get a cleaning rod that's made for m16, it'll fit the Yanmar heat exchanger tube?
thats great that you had such a simple fix.......has anyone noticed reading all these threads on repair how it seems to be more detective work than anything else
After 30 years of successfull industrial trouble shooting here is my Order of Battle....
1) Check the alarm sensor
Buy a $6 digital cooking thermometer or laser pointer. Run your engine till alarm. Listen for the water burping in exhaust. Shut down engine. Quickly touch or laser the anti-freeze tank. Open the fill cap slowly to prevent hot sprayback, stick in thermometer and if it is about 160-180F
Then... it is the Sensor/alarm.
If cool anti-freeze/fresh water, then go to step 2.
2) Check the ocean water system flow
If you heard no spitting/burping in your exhaust in step 1, then it means little or no sea water flow.
Pump impeller replacement is not JUST impeller to the standard rubber flex vane pump. You have a wear plate and a paper thin gasket, if not right, that pump will "by pass". If the old pump impeller had missing rubber... ouch.
Clean your pump stainer. BTW the '4" water' means that the top of that hose is at least 4" below the Actual Water Line. If it was say 12" below AWL you have a restriction from that hose back to hull. In other words you can measure pressure drop (restrictions) by inches of water spout relative to AWL.
3) Sea Water/Anti-freeze heat exchanger
If sea water flow is good then this should not be the problem...
If not, that has to be pulled/cleaned of fouling from crud or rubber impeller parts (see above comments and tips).
Why did I do 2 & 3 before the next part 4+? It is a toss up, but i think routine required maintenance is easier to check and clean before engine component work.
4) Replace your thermostat
I would do it new versus test. They are very cheap and you get renewed.
5) Get a Mechanic
Sorry but it highly unlikely that the anti-freeze coolant system beyond a full liquid/theromstat is the problem. and the rest "aint routine":cry:
We have all been there probably with vehicles or boats...
Good luck
Jim..
1) Check the alarm sensor
Buy a $6 digital cooking thermometer or laser pointer. Run your engine till alarm. Listen for the water burping in exhaust. Shut down engine. Quickly touch or laser the anti-freeze tank. Open the fill cap slowly to prevent hot sprayback, stick in thermometer and if it is about 160-180F
Then... it is the Sensor/alarm.
If cool anti-freeze/fresh water, then go to step 2.
2) Check the ocean water system flow
If you heard no spitting/burping in your exhaust in step 1, then it means little or no sea water flow.
Pump impeller replacement is not JUST impeller to the standard rubber flex vane pump. You have a wear plate and a paper thin gasket, if not right, that pump will "by pass". If the old pump impeller had missing rubber... ouch.
Clean your pump stainer. BTW the '4" water' means that the top of that hose is at least 4" below the Actual Water Line. If it was say 12" below AWL you have a restriction from that hose back to hull. In other words you can measure pressure drop (restrictions) by inches of water spout relative to AWL.
3) Sea Water/Anti-freeze heat exchanger
If sea water flow is good then this should not be the problem...
If not, that has to be pulled/cleaned of fouling from crud or rubber impeller parts (see above comments and tips).
Why did I do 2 & 3 before the next part 4+? It is a toss up, but i think routine required maintenance is easier to check and clean before engine component work.
4) Replace your thermostat
I would do it new versus test. They are very cheap and you get renewed.
5) Get a Mechanic
Sorry but it highly unlikely that the anti-freeze coolant system beyond a full liquid/theromstat is the problem. and the rest "aint routine"
:cry:We have all been there probably with vehicles or boats...
Good luck
Jim..
.223 should fit
Ken
I haven't tried with an M-16 rod, but the .22 rod had plenty of clearance. The M-16 should be a .223 inch diameter so I would think it would be just fine.
Ken
Strangest one I have come across, buddy found a headless eel stuck right at the intake to his impeller.
please let this one drop. Boats used to have grills over water thru hulls, but few have the extra expense of that now. Unfortunately now innocent wildlife gets needlessly killed and clogs up things everywhere.Should we even ask where the head was found
I was helping a buddy work an overheating problem on a raw water cooled, Yanmar 2 QM 20 .. We found most of a small fish in the thermostat.. On another friend's boat, found a weak suction hose between the strainer and pump that would collapse at high RPM.. On my boat, I had the bad gasket on top of the strainer. It would leak air into the suction side at high RPM but not leak water when engine was not running.. Puzzles to solve.. like Soduku, only better.
Not to play one-up-manship Kloudie, but I once found a condom blocking the through-hull intake. Whoever discarded it overboard surely had more fun than I did getting rid of it.