overheated motor!

[airlock]

I suffered my first overheating issue and really the first problem with my trusty 135 black-max.

On Monday i fancied a quick river fish with a mate, all was well on the way down the river, about 30 mins WOT with no issues and then anchor up to wait, while there i topped up the tank. When i went to restart the motor the bastard wouldn't start, i took a while to figure out that this was due to flooding, never had this happen before and still not sure why or if it might be relevant??

Any way got her running and ran about 5 minutes up the river and had a fish. When we came back I opened up the throttle to the sound of that high pitch panic buzzer that my mate told me meant she was getting hot, had a peek over the back and no tell tail to be seen at all. I decided to nurse it about 2 minutes at low revs to the bank, stepped off and the motor was really smoking with streams coming out of the tell tale hole, not good.

I'm guessing the impeller has died on me so the plan is to change this, the plugs and run a compression test while i'm there. What else should i be doing at this point, i imagine the remains of the impeller will be pretty broken up and i'm wondering if any of the rubber may be stuck in the system, is there a simple way to check and clear them if they are?

[JulianDeMarchi]

I suffered my first overheating issue and really the first problem with my trusty 135 black-max.

On Monday i fancied a quick river fish with a mate, all was well on the way down the river, about 30 mins WOT with no issues and then anchor up to wait, while there i topped up the tank. When i went to restart the motor the bastard wouldn't start, i took a while to figure out that this was due to flooding, never had this happen before and still not sure why or if it might be relevant??

Any way got her running and ran about 5 minutes up the river and had a fish. When we came back I opened up the throttle to the sound of that high pitch panic buzzer that my mate told me meant she was getting hot, had a peek over the back and no tell tail to be seen at all. I decided to nurse it about 2 minutes at low revs to the bank, stepped off and the motor was really smoking with streams coming out of the tell tale hole, not good.

I'm guessing the impeller has died on me so the plan is to change this, the plugs and run a compression test while i'm there. What else should i be doing at this point, i imagine the remains of the impeller will be pretty broken up and i'm wondering if any of the rubber may be stuck in the system, is there a simple way to check and clear them if they are?

To me it sounds like the thermo has gone. My Merc did this exact thing when the termo went.

[Fed]

You could have picked up a plastic bag give it a run & see if it now pumps any water.

[Cloud_9]

check thermostat and then impeller, you can back blow with compressed air via any water line under the cowl.
plastic thermos can melt then fail.

[Noelm]

Not too sure running an overheating motor even at low revs was a wise option, especially seeing as you were in a river.

[GBC]

^what he said. If the buzzer kept going you may well have made a bad thing worse. Time to see a proper mechanic.

[airlock]

well thanks for the advice guys. after a good compression test at home but no bench to pop the leg on I ended up taking it to a marine mechanic for a proper check over. it appears i got lucky and the extent of the damage was a failed impeller, no indication as to why and it was fresh on less then 6 months back but i suppose it's just one of those things. thermo appears to be fine and apparently despite the recent issue the motor is looking in good shape so hopefully its going to be trouble free for a nice long time.

[Flex]

I had two brand new impellas fail on me. Had a set of twin outboards and both impellas malfunctioned within a few days of running. Can sometimes happen if your running the motor over shallow ground and trim it up a bit far for a brief moment. Or they are few old off the shelf? Seems to melt them a bit. When I pulled my impellas out they looked ok and they both worked at wot. But as soon as I would idle the motor would slowly over heat. I actually melted the housing by a few mm to cause lack of water flow.