G2 operating temperature range

[SEAHORSE]

If it is still a thick liquid and tacky, still smelling like cottonseed oil, then it should be OK to use. If it is like pudding, toss it out.

[Millertm]

It was nice in NY today so I replaced the pump. The old pump was so bad. It was burnt and melted. I can't believe that it could generate any pressure. Even the housing was melted. I never had any alarms so I can only assume it happened when it was a demo. Anyway, here is a picture of the old pump.20220505_134535.jpg

[86 inches]

That looks horrible. It will be interesting to see what the pros say about that

[veryspeedy]

Dude ! That is crazy, when mine had low pressure it still looked brand new . That is from check starting the engine on the trailer with no water I believe for sure .
The pump will over heat I 2 seconds like I said in my first post .
I guess we all learned something today.
I would make sure your lower pick up screen s are clear and. Nothing stuck in water passages

[Millertm]

I would like to test it out in my driveway before going to the lake since it is like an hour away. What is the best way to run it out of the lake?

[veryspeedy]

I have run mine on the hose screwed into the flush port on back of the engine . I still would not run it long .
Also make sure to turn water.on first before you start
My service manual is not here it up at.my cottage with the boat but my memory says ok on the flush port. The tell tail should be spraying out hard with new pump.

[blkfalc4]

Duck tape closed the low water pickup screens, install the muffs on regular intakes, add water, run.

[86 inches]

If you are going to use muffs, you might want to remove the intake screens to get a better seal. If you are going to use the rear flush port, run only with your engine vertical... do not tilt. BRP also offers an accessory front flush kit that installs under the front cover. Or... you can use a tank. A 100-150 gal polyethylene stock tank works great.

[Millertm]

Thanks for all the advice. I made a trip to the lake to be safe. The new pump worked great. Idle pressure was 7psi.

3850rpm 26psi 119F
4100rpm 27psi 121F
4600rpm 31psi 128F

The idle pressure was significantly better but the higher RPM pressures were only a little higher and the temps at all RPMs were significantly lower. I should have done this when I first noticed it when I got the boat

[86 inches]

Did you check your thermostats and PRV. Running too cold ain't so good either. You didn't list your idle temps.

This winter I noticed that my temps weren't coming up like they should. I replaced the thermostats and that fixed that. Now, within 5 minutes or so of idling it comes up to 145 like it should

[Millertm]

I did not pay attention to the idle temp.

I did not check the thermostat or pressure relief valve but I did buy new ones just in case. I didn't really think about it being too cold, I was just excited to see the tell-tale stream and good pressures. Now that you mentioned it I'll have to collect some more data. I did not run it long and the lake temp was only 59.

[posmallie]

So I have a question about a low running temperature. I have a 150 G2, and when it is cold, I will sometimes have a running temp (3500RPM) of 112-120 degrees. Sometimes it also runs 144-157 degrees. Is this the result of the cold water or a thermostat issue?

[Fireball]

I also have COLD temps at full throttle. Water temps mid 40's and at full throttle engine temp at 102 degrees. Prop quite black and so were the plugs, however the 90 HO outboard runs great at all RPM's. Any thoughts ? ? ?

[86 inches]

I did not pay attention to the idle temp.

I did not check the thermostat or pressure relief valve but I did buy new ones just in case. I didn't really think about it being too cold, I was just excited to see the tell-tale stream and good pressures. Now that you mentioned it I'll have to collect some more data. I did not run it long and the lake temp was only 59.

Thermostats control your engine temp at idle and below 2500 RPM and open at 143. Above 2500 RPM or 28 psi the PRV opens and you will see your engine temp drop - especially if you are running in cold water. If you run for a short time you might not see it climb much. I think that is normal. The G2 should throw a code if there is a significant problem. Also, the values Dan listed above (140 +/-10 idle, 150 +/- 10 WOT) are given for a very specific procedure with very specific parameters described in the manual as an Engine Temperature Check on pg 218. While I don't believe you can apply those values to all conditions, those numbers are pretty much what I see when I'm not running on the extremes of environmental conditions.


We all are aware of the dangers of blasting off early in the morning before the engine has come up to its operating temp. I believe the safeguard there is a Code 58 or 59 for starboard and port sensors respectively. "If the cylinder head does not reach operating temperature (122F below 1000 RPM) in 10 minutes."
When I replaced my thermostats I was surprised at the amount of corrosion on the seating surface of the heads. Water was definitely leaking past the thermos. After cleaning that up, I used Yamabond to glue the seals to the head and installed new thermostats. My engine comes up to temp much better now.








5 years. 270 hours

[Millertm]

That corrosion looks nasty. Thanks for the pictures. Now I have something to compare to if my temperatures remain low when I put the engine through more testing.

[veryspeedy]

Last Sunday my engine had warmed up to 147 made ten min run to my spot temp dropped to 120 decided to idle over the spot and graph temp don't get over 128 Ran back ten min water temp drop to 112 . This always concerns.me as well no alarms max rpm was 5k on this outing ,no lights or warnings .
But is concerning to say the least. My years of automotive knowledge says this could stick a ring and crack the top of piston off.
But seams no not Efect this engine so far.

[Bighare2]

But this is not an automotive cooling system. The pressure relief valve dumps water at higher speeds and it’s normal to see a temperature drop.

[veryspeedy]

It has nothing to do with open or closed cooling systems .
It has to do with block / piston expansion rates and ring gap clearances
engine builders will tell you if you run a engine high rpm the piston may expand faster than block and ring gaps could but together in a marine environment.

[Millertm]

I went to the lake again today and did a more complete test. I let the engine warm up for about 10 min while I got my gear ready.
Idle was 490 rpm, 7 psi, 127F. Lake water temp was 64F. Then I ran it around the lake and got
1720 rpm, 16psi, 139F
2370 rpm, 21psi, 143F
3230 rpm, 26psi, 146F
3930 rpm, 25psi, 143F
4600 rpm, 29psi, 140F

I believe these are all reasonable according to my service manual.