2000 225 PM getting hot.

[AlaskaStreamin]

So here’s how this started.
Ran motor on the nose cone flusher night before an early morning departure to go boating.
My fault . mis placed the flusher on LU and didn’t get good coverage so pump ran dry.

noticed no water at telltale or exhaust and shutdown within 60 seconds.

Dropped lower and replaced complete pump assembly. impeller was smeared but in tact.

pulled stats and ran garden hose on water tube to flush block.

re-assembled and test ran in tank. Everything went as usual. Pressure and water at telltale. Temps at the 1/4 mark. Tested alarm sensor by grounding wire . Got alarm so that works.

once on step, temp gauge rises steadily, no alarm , pressure at 10#. Solid telltale stream.

pull stats and same scenario.

pull powerhead, complete disassemble , new poppet assembly, disassemble 2piece exhaust divider check water passageways , nothing plugged. All water passages checked, water tube inspected . Replaced temp sensor.

put motor on my other boat.

same problem. In tank idling, 5# pressure, telltale lazy till tstats open then strong stream, port bank 113* laser thermometer…gauge shows 120* . Stb bank 123* . Per laser thermometer.

went to lake and same problem. Idles at 120* get on plane and watch gauge rise. 10#_12# on step cruising. Jack motor up/ down trim in/ out. Punch it to 6000 rpm’s. Briefly, no change. Just keeps rising. At 225* no alarm but I slow down and idle back to launch.. (my fault for leaving laser thermometer at home) would like to know if it’s really this hot. New sender tho…

im baffled. This shouldn’t be happening.

does anyone have any idea what else there is to look at?

[LakeFever]

Verify temp with heat gun at head to rule out sender or gauge. Many here suggest to clip some of the spring off the poppet. Search that out I don’t know how much to cut

[XstreamVking]

Buzzer should have gone off at 180 At 225 engine would be cooked. Seems gauge is wrong. I cut 1 coil off the poppet spring for hot water operation. Some engines need it, some don't.

[tlwjkw]

no buzzer, no over heat... very, very rare for tha sensor ta be wrong... don't trust any temp gauge reading till its proven accurate...

[rjdubiel]

We had something similar last week, the gasket under the water pump base tore somehow, maybe too much hose water pressure, maybe too tight on the water pump cover, not really sure, but that gasket between the lower unit and the water pump base was bad. replaced and all good. maybe worth a check if you did not pull the water pump base when you did the pump the first time.

I heard you may make the trip to FYNBAHR? Is that true?

RJ

[LakeFever]

We had something similar last week, the gasket under the water pump base tore somehow, maybe too much hose water pressure, maybe too tight on the water pump cover, not really sure, but that gasket between the lower unit and the water pump base was bad. replaced and all good. maybe worth a check if you did not pull the water pump base when you did the pump the first time.

I heard you may make the trip to FYNBAHR? Is that true?

RJ

common. In some interesting conversation with an old and experienced racer it was proven to me why this happens. Once you’re at high enough speeds you don’t even need a water pump. The pressure of the entry is higher than the pump could ever reach. When this gets really high it blows out the gaskets on the water pump housing. I’ve seen this now a few times on lowers. This came up because as I use my jack to aid in cornering my water pressure spikes up to 30psi sometimes and that’s when I learned about this. I was offered a bet that the water pump can be completely removed so long as speeds are kept up the water pressure would be just fine. I’d like to see this before I tried it on my own motor but the point was made.

[rjdubiel]

The water pump actually is like a pressure regulator at speed, like you said i have been told the same, no need for a water pump at speed as the water is forced into the nosecone and up into the power head. I wouldn't try it either but.......

[aj06bolt12r]

Like others have said.. If the buzzer isnt going off and you verified that it works its probably not really getting hot. Temp sender is based off of resistance to ground. Make sure temp sender has good contact with the head. Make sure the ground is clean. Make sure the wiring to the gauge is good and connection at the gauge is good. Could also be the gauge itself but I doubt it.

[rjdubiel]

everyone remember there is a temp sensor and a hot buzzer sensor, different heads, different sensors. I am guessing it did not get to 225 actual degrees F. THATS HOT! hopefully it gets figured out as i am betting on the gasket under the water pump base is bad.

[Merc 2.5]

So here’s how this started.
Ran motor on the nose cone flusher night before an early morning departure to go boating.
My fault . mis placed the flusher on LU and didn’t get good coverage so pump ran dry.

noticed no water at telltale or exhaust and shutdown within 60 seconds.

Dropped lower and replaced complete pump assembly. impeller was smeared but in tact.

pulled stats and ran garden hose on water tube to flush block.

re-assembled and test ran in tank. Everything went as usual. Pressure and water at telltale. Temps at the 1/4 mark. Tested alarm sensor by grounding wire . Got alarm so that works.

once on step, temp gauge rises steadily, no alarm , pressure at 10#. Solid telltale stream.

pull stats and same scenario.

pull powerhead, complete disassemble , new poppet assembly, disassemble 2piece exhaust divider check water passageways , nothing plugged. All water passages checked, water tube inspected . Replaced temp sensor.

put motor on my other boat.

same problem. In tank idling, 5# pressure, telltale lazy till tstats open then strong stream, port bank 113* laser thermometer…gauge shows 120* . Stb bank 123* . Per laser thermometer.

went to lake and same problem. Idles at 120* get on plane and watch gauge rise. 10#_12# on step cruising. Jack motor up/ down trim in/ out. Punch it to 6000 rpm’s. Briefly, no change. Just keeps rising. At 225* no alarm but I slow down and idle back to launch.. (my fault for leaving laser thermometer at home) would like to know if it’s really this hot. New sender tho…

im baffled. This shouldn’t be happening.

does anyone have any idea what else there is to look at?

I been kinda goin thru same thing, mine has never reached 225 on guage tho. Over last winter I decided to put in temp guage (merc) and use stock sender. 1st trip out it climbed to 170 pretty quick ( head temp) I turned around and loaded it up , I've been thru 3 or 4 pumps on 2 diffrent lowers, poppet cutting springs etc, thermostats to restrictor washers with every size hole u can think of. I now have a sender in each head with 1 guage at dash and I use a toggle switch to swap back and forth for temp on each head instead having 2 guages. When my guage hits 170, thermostats are just starting to open around 140-145 water temp, the infrared says head temp is around 160-165. Starboard side get few degrees warmer on long no wake zones , once on plain guage will read 150ish. Give or take. I have installed a water temp guage recently but my sender was junk, so soon I get a sender for water temp ill be able compare better. My question to everyone else is , what kind of head temps do u normally see with 145* water temp?

[AlaskaStreamin]

Thanks for all the replies guys.
I’ve been checking my email and notifications are on but nothing showed up. Glad I checked my post and was surprised to see all these.

so two boats which means two gauges and a new sender so that should be ok.
The sensors for both sides read head temp not water temp. When I’m using the laser gun, I try and get the dot next to the spark plug washer.

I did replace the entire water pump with a nice clean used one with new gaskets and impeller.

then when I broke it down I bought a new WP assembly and installed.

I’ve read every overheat thread out there and this defies logic.
I will go out again shortly with the laser thermometer. I’m still baffled at why both gauges read high weather it’s true or not.

rj, yes we are planning on running to Fynbar this year.
packing the 280 in the truck to sell or leave with Superior marine &rv to sell.

either the Virage / 300 PM or the Voyager with a spanking new 200R.

[whipper]

Bet cha with the laser if temps say 220 on the gauge the stream is saying A OK and heads acceptable. :] i hope for anyway. Make sure ya let us know how this worked out. :]

[Merc 2.5]

Does anyone know if this is a water temp guage or head temp ? Since it had 145* in middle I thought maybe it would be head temp for outboard but I'm thinking prob water temp , I know my other guage faria is water also from a inboard. How off would these be with mercury head temp sensor u rekon?

[LakeFever]

I had all sorts of confusion during my break in cycle with temperatures. I took a laser temperature gun out and after a ten minute run I took readings off the head and spark plug. 143 degrees. Haven’t worried about it since. The bunny in one of those threads I made during this confusion said he doesn’t even run a temp gauge just a water pressure gauge

[rjdubiel]

any temp gauge needs to be tested to make sure the gauge is calibrated to the sender. Get out the pot of water and the thermometer!