Overheating of the collectors on the move under load, loss of power (emergency mode).

Best · May 21, 2023

I have a PCM ZR409 engine, version without antifreeze (water circulates in the block and manifolds). The problem started two years ago. The symptoms are the same as here: http://www.centurioncrew.com/index.php?/forums/topic/11155-fault-codes/ Also errors SPN: 441, 442. This year, after reopening, first these errors were issued even at idle. After replacing the impeller and thermostat, the problem began to appear only on the go under load, as in the past two seasons. When I ride a wakeboard, or when I go with a left wave for a surfer (the load is more), I get errors on overheating of one or two collectors. Occurs after approximately two minutes of wakeboarding or five minutes of surfing. At the time of the error, the emergency mode is activated for a short time, after a few seconds of reset, the power itself is restored. This is enough for the wave to break and the rider to fall. But if the engine is turned off at this moment, the water circuit starts to go crazy: it makes sounds of hissing or gurgling in the area where water enters from the v-drive into the thermostat housing, and pressure drops in the cooling system are felt on all soft hoses, video How soft hoses twitch and shrink for a second. As if the water boils in the hoses for a second, then it does not boil for two seconds, and history repeats itself. After ten seconds of idling - everything is fine until I again give the load. The following work was carried out: replacing the impeller assembly with the housing, replacing the thermostat assembly with the housing, checking all the hoses, flushing the engine and transmission heat exchangers, flushing the manifolds with acid (now they shine like new inside), replacing the emwt sensors, checking the v-drive on object of contamination. Can exhaust risers affect overheating in this way? Has anyone encountered such a problem?

Edited May 21, 2023 by Best
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Troy. R · May 22, 2023

It certainly sounds like you have a leak. Do you have steam coming from anywhere when it starts to overheat?

Best · May 22, 2023

No, vaporization is not visible. Everything in the engine compartment is good and dry. The risers are a little warm on the move, but when I walk under load they become a little hot, you can hold your hand for a long time, they don’t burn. The temperature of the water in the unit does not rise above 75°C. Previously, the engine temperature was raised to 80-82°C with two different thermostats. I opened the thermostat forcibly to rule out a malfunction of the two thermostats, but this only delayed the occurrence of the error. If you ride without a thermostat, the error does not occur, but the engine does not warm up above 56 ° C.

Best · July 27, 2023

Thanks for support. Problem solved. All the fault was incorrectly selected anodes. They were installed too deep into the exhaust manifold and blocked the water passages from cylinders #7 and #8. Because of this, the collectors did not receive local cooling, a vapor lock was created and the water in the collectors began to boil. Installing conventional plugs in place of the anodes solved the problem.