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350 MAG MPI stalled. Will not restart

S

Stelios

Member
My 2005 350 MAG MPI has been running perfectly. Suddenly while cruising speed she quickly bogged down and stalled. Will not restart. In the spring I changed cap and rotor. After stalling I replaced IAC and cool fuel filter just to try. No help. She sounds like she wants to fire up and start (fuel relay clicks on and spark) but after a few cranks she spits and coughs and thats that. Any ideas where to start?
 
Stelios said:
ok
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makomark said:
If it has a good spark, I'd check the fuel pressure in the rail...
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rail pressure checks out 38-40 PSI with ignition on.

New problem
although my batteries are good I lose all voltage on port side gauges and ignition. I have a smart charger plugged in with AC at the dock. voltage goes to zero. no crank. nothing. I had noticed when she first stalled and i tried to restart, cranking slowly became weaker. Earlier I could still crank fine with the parallel booster switch. But now.... nada. nothing.
 
Fuel pressure is a little low but I wouldn't worry about that for now...

On the voltage drop, I would suspect a bad connection (or wire) in the battery leads (to the engine)...
 
makomark said:
Fuel pressure is a little low but I wouldn't worry about that for now...

On the voltage drop, I would suspect a bad connection (or wire) in the battery leads (to the engine)...
Click to expand...
but would that also give low voltage at the ignition switch and gauges?
Theee is zero room to reach around these engines on a Searay!
 
It's a twin-engine boat? twin ignition keys too?
What engine side died/causing the issues?
If the port engine died and now the port (Left) gauges are not working properly then yes it very well could give low or now no 12v power to the ignition / gauges to that side as often the wiring ran from each side engine runs to each side of the helm that would power that side all the while bearing in mind that you may also have a battery isolator especially with the design battery switch you sound like you have possibly causing power issues too from say an internally or externally bad, corroded, loose connection somewhere to it or at the engine starter cable connection to all other power connection points of the engine.


Also push in (or up) and inspect to see what design 50‑amp circuit breaker your engine has... Is it a red push button type or a yellow‑flag‑type circuit breaker? Does it look like this, https://www.ebay.com.au/itm/50-AMP-...of-12V-24V-32V-Fuse-Manual-Reset/302887638171
Or this, https://www.amazon.ca/Mercruiser-Circuit-Breaker-88-806950-88-11178A01/dp/B07GD4335W



Some ideas to follow along with if needed,

Mercury 6.2 ECT DTS Axius Voltage Issue

Yes, I was thinking either the ignition switch or the alternator . . . something is dragging the voltage down. Or adding voltage when not supposed to.:unsure:🤷‍♂️ That's when in your case you'll want to compare the other engine to see if it's acting the same or not to see what direction you...
forums.iboats.com forums.iboats.com

Mercury 6.2 ECT DTS Axius Voltage Issue

I'll have to see where the port engine clean power cable is located. You must This is a part of fundamental electrical troubleshooting isolation View entire vessel electric systems independently. Key to figuring out your specific issue
forums.iboats.com forums.iboats.com
 
Keep in mind the + terminal on ths starter is inacessible without removing risers, etc. Its being done so far by braile.

With ignition on and if i jiggle wires at the starter I go from zero to 12.4V - same as batteries. But that dosnt last long until i jiggle again. If I short across the solenoid i get a very weak attempt to start then zero volts. (drained)

So it all points (i think) to a loose or bad pos connection on the starter lug.

I can get 12.4V at the alternator orange wire and on the 50amp circuit breaker. But I can never get any voltage at the solenoid red wire.
😡
What to do?
 
Know of any young kids with long arms in the area that might be able to get down there to help figure something out? Don't underestimate any female's either as they can be capable of doing great things in hard-to-reach areas.

Take a video of the starter area so you know what to prepare for on your phone.

Before putting wrench on the starter nut, you'll need/want to fully disconnect the battery to be safe... Don't fully trust the battery switch in this case.

Keep in mind that the cable/s could also be corroded and needs to be replaced.

Keep us updated, Good luck.
 
And we're back!
Turned out the distributor rotor had blown up. replaced and she runs great again. But it did reveal the barrel harness connector seems loose. jiggle has it in place working now. but have to solve that.
 
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