New Mercury 600 starting problems when hot
08-25-2015, 04:32 PM
#21
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Location: Aliso Viejo, Ca
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On computer controlled marine engines you have 7 modes of engine operations and the clear flood mode is one of them but this is not active for ECM and PCM 555. It is active for MEFI systems. This is for if the engine gets flooded of fuel, it can be cleared by doing so - Advance the throttle to 1/2 min to 3/4 open. when the throttle position sensor reads between 50 % to 75 % at cranking rpm the ECM will not fire the fuel injectors at all. This allows air into the engine but no fuel so the can start basically as a non flooded engine. Once the engine starts and exceeds over 300 rpms the ECM cancels the clear mode and then enters running mode. Again not active on ECM 555 and PCM 555.
If you have to advance the throttle everytime to get your MPI marine engine started - you have a problem somewhere in the system. It can even be a sensor reading input to the ECM especially for the IAC and or coolant temp sensor and or the TPS sensor and of course fuel related problems can be adding to the list.
If you have to advance the throttle everytime to get your MPI marine engine started - you have a problem somewhere in the system. It can even be a sensor reading input to the ECM especially for the IAC and or coolant temp sensor and or the TPS sensor and of course fuel related problems can be adding to the list.
08-27-2015, 05:04 PM
#22
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Interesting, sure sounds like vapor lock, that I have experienced on my old 35 Nordic Flame that had 502 MPI's. I have 600SCi's in the 388, and they have about 120 hours on them, and I boat in air temps,85-95, and I have never had a problem starting, or anything for that matter, my 600 SCI's have been very reliable, (knock on wood). BUT, I will say that I always idle for a fair amount of time, (Manatee Zones, GRRRR) and always open my hatch and let them cool whenever possible. Maybe try taking a towel and soaking it in the ice cold beer cooler water and then sit the cold towels on the fuel rails to cool the rails and the fuel and give it a try... Seen drag racers do this in the Florida heat....
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08-30-2015, 11:28 AM
#23
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I think my post # 20 was taken wrong or my info was not clear enough.
1. the OP does not have a MEFI - ECM - it will be a PCM 555 Merc specific flash
2. post # 8 as I believe 99.9% its vapor lock as well but what is causing the vapor lock sometimes and a lot of times there can be something causing VL and is not E 10 related specific ? We have noting but E 10 here in the area and our weather during the whole summer is hot as hell plus are lake water temps is the hottest around. Most properly working and properly set up fuel systems for the marine engine do not experience vapor lock using the correct gas blend as well. I said most not all.
3. Clear flood mode if somehow the MEFI based engine gets flooded there is a clear flood mode to try to see if that will aid in starting the engine. Again your engine is most likely not flooding (gas) and is not MEFI based anyways.
There are things you can do to help against vapor lock.
1. the OP does not have a MEFI - ECM - it will be a PCM 555 Merc specific flash
2. post # 8 as I believe 99.9% its vapor lock as well but what is causing the vapor lock sometimes and a lot of times there can be something causing VL and is not E 10 related specific ? We have noting but E 10 here in the area and our weather during the whole summer is hot as hell plus are lake water temps is the hottest around. Most properly working and properly set up fuel systems for the marine engine do not experience vapor lock using the correct gas blend as well. I said most not all.
3. Clear flood mode if somehow the MEFI based engine gets flooded there is a clear flood mode to try to see if that will aid in starting the engine. Again your engine is most likely not flooding (gas) and is not MEFI based anyways.
There are things you can do to help against vapor lock.
Last edited by BUP; 08-30-2015 at 11:43 AM.
