502 efi problem
 

I think there was someone that had this same problem but I can not remember. Engine will not rev past 2000 rpms without sputtering and popping under load and in neutral but if the jumper for base timing is left in there is no issues boat runs fine just lacks power due to no advance. Scanned with DDT no codes and data all looks normal no power reduction mode or anything like that. Fuel pressure 40 psi ,cap, wires, plugs ,dist module,water seperator all new and tried an ECM. ????? anyone got any ideas?????

i just had simular problem, and the filter screens in the VST tanks in the back of motor were getting blocked. easy fix. pm me if you want i can tell you have to fix..

The vst fuel system was removed and upgraded with aeromotive

i was told by a few people that the stock distributors wear out, and the magnetic pickups fail around 500 to 600 hours...when i was tring to figuare mine out i called pression marine and he said to buy a msd dist or a dui replacment one. they are efi distribs.

I checked the resistance of the pickup and put in a new 8 pin module. Is there an issue with the distributers ??

If the tach is jumping all around it could be the distributor shaft loose. Pull the cap and look for any oil trace, also see if there is side to side play, any at all and it has to go. Also unplug your oil pressure switch (not sender, the little one), water temp switch, and drive reservoir connector one at a time and see if one of those are shorted, that will limit power without a code.

I checked all the senders that could put it in power reduction mode also monitored with DDTand the readings are all good??? But that is exactly how it runs(power reduction mode)