1995 Mercury Black Max 200 EFI Stalls

mram10us

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Feb 9, 2015
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New here, so forgive me if this is a basic fix. I have been scouring this site and youtube to find help, but still no clear cut answer.

Here is the problem:
Start the boat and idle out from dock to open water for 5 minutes.
Push and throttle and it bogs like an old car running rich.
It then dies.
Only remedy I can find is put in neutral and rev motor for a few seconds, like it is cleaning it out. After, it runs fine for a time.
Doesn't seem to happen due to heat, because it happened in 45 degree weather last week and 100 degree during the summer.

What I have fixed:
Some of the fuel line with ethanol compliant fuel injection line
Fuel filter
Most fuel hoses on the motor that I could find
Spark plugs

What I plan on next:
Finish replacing all fuel lines from tank to engine
Find a flywheel puller to test stators (?) Know nothing about this one
Test fuel pressure

Any advice is welcome and thanks in advance.
 
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wired247

Lieutenant Commander
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Oct 8, 2011
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1,557
You are losing fuel pressure Fuel pump or clogged fuel filter.
 

mram10us

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Feb 9, 2015
Messages
25
FIXED!!!
UPDATE:
Installed a fuel diaphragm kit and it ran great. Fixed the problem. Now, I found out my water pump is not working. Always something. Replaced the thermostat while I was at it and need to drill some holes to allow a little cooling throughout in case they don't open. Don't trust those things.
 
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mram10us

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UPDATE:
I also cleaned the high pressure pump filter(port side top front of engine) while replacing all fuel lines. It had lots of junk in there. After re-timing the motor(+4idle, +22 cranking btdc), it seems to run great. No more delay or bogged down feeling. Hope this helps the next guy.
 

mram10us

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Feb 9, 2015
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Well, after running it most of the day, it did the bog down thing again. Back to the drawing board.....
Thoughts:
1. The charging system is not working. Could it have something to do with the max of 8mph/bog?
a.Stators seem to check fine, but voltage regs are cooked.
2. I did not take the fuel tank pickups out of the tanks to make sure they were good. All fuel lines and filters were replaced.
3. Should I replace all the vacuum hoses on the engine? Could that cause the rich/lean condition with the bog?
 
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Faztbullet

Supreme Mariner
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Mar 2, 2008
Messages
15,589
Is it overcharging???? If so it can make the ECU at goofy and overheat fuel pump. Low voltage can do basically so of the same..
 

mram10us

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Feb 9, 2015
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Not overcharging, since it isn't charging at all :) Battery voltage getting low cause this?? I just ordered 2 new CDI volt regs since mine were fried. hopefully it fixes the charging issue. Not sure if stator is acting up when hot. Does seem to give me more problems in the summer.
 

wired247

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Oct 8, 2011
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if the voltage drops too low it goes into suck driving mode at the ECU level.
 

mram10us

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Feb 9, 2015
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Here is the dumb question ..... what is "suck driving mode"??

Also, ordered 12' of new 1/8" bleed hose to replace all. Maybe that is tricking my system.....
 
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wired247

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Oct 8, 2011
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Suck driving mode is when it wont start worth a damn or idle for crap. Classic low voltage problem with EFI's. Does the same thing when it overheats.
 

Faztbullet

Supreme Mariner
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Mar 2, 2008
Messages
15,589
Where are you replacing these bleed lines as a EFI 's are capped off???
 

mram10us

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Feb 9, 2015
Messages
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I should probably call them vacuum lines. Sorry about the confusion
As for the sucking, I will fix the charging system and let you know if it is a low voltage thing. Thank you for the help. Keep the ideas coming.
 
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Dukedog

Captain
Joined
Oct 6, 2009
Messages
3,235
sounds like ya missed tha little cone shaped filter in that "U" shaped fuel supply lihe between tha vst and pump? if tha round screen filter was full a junk it will be also.......
 
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