2000 350 Mag MPI won’t start…

Luna Sea

Lieutenant Junior Grade
Joined
May 20, 2002
Messages
1,069
Guys, I’ll try and keep it short. <br /><br />Replaced cap, rotor, ign. sensor assy and coil a few months back. Boat ran good, for a half hour, then died. Talked to local marina’s mechanic, he suggested finishing the tune up (plugs and wires) and hooking up a portable fuel supply, which I did. The portable fuel supply was suggested because I mentioned the motor had been breaking down after a half hour use at anything over 3200 rpm’s, so I suspected fuel problems. It still wouldn’t start so I got it towed and after a half day on the job they determined I bought a bad coil, which they replaced. The original coil was the cause of the motor breaking down at high rpm’s we determined.<br /><br />The boat ran fine for a month or so after that, with coil #3 on there, and now it’s down again! I’ve been spraying starting fluid in there and gone through a couple of charged batteries with no luck starting it. I had a local wrench (friend of a friend) out there for a brief period between rainstorms 2 weeks ago with a test light and he seemed to think I had the “spark” required. We didn’t do any major tests though. <br /><br />I’m looking for a tow back to the marina but that ain’t gonna happen till next week. I’m gonna try again Saturday to get it started. I do have a manual but have to admit electronic’s testing’s not my thing. Friend’s friend may come out sat, but I’m not sure what he can do without the “computer” hookup…..<br /><br />Are the coils on these things that flimsy?<br /><br />Is there something that could be blowing coils up?<br /><br />Engine’s turning over fine, just doesn’t wanna start! <br /><br />Kind of frustrating. Open to suggestions…..<br /><br />Thanks for looking in<br /><br />Oh, one other thing. New ign. sensor has ground wire, old one didn’t, I’ve disconnected it and grounded it to a couple of different places as it wasn’t grounded properly the first time. Would doing this without disconnecting the battery harm it?<br /><br />Should I spend $50 on yet another coil or just bite the bullet and head for the $100 an hour place next week?<br /><br />And I heard something about starting fluid not being good for fuel injeced engines? Any comments on that?
 

bomar76

Lieutenant Commander
Joined
Jun 27, 2002
Messages
1,963
Re: 2000 350 Mag MPI won’t start…

You need fuel, compression, and spark to run.<br />You need to determine what it is you are missing to determine why it won't start.<br />Coils do go out, but 3 in a row is a longshot.<br />Take the boat to a real marine mechanic before you load it up with enough ether to bend a rod.
 

rodbolt

Supreme Mariner
Joined
Sep 1, 2003
Messages
20,066
Re: 2000 350 Mag MPI won’t start…

if it wont start with starting fluid odds are good its an ign failure. make sure the stop lanyard is not tripped. after that its time to follow the flow chart in the manual and find out what broke. dont need a puter for most of it. as far as starting fluid, I really dont reccomend it but it wont hurt anything unless your engine uses glow plugs and not spark plugs. I have used it to isolate fuel or ign myself in a pinch.
 

Dunaruna

Admiral
Joined
May 2, 2003
Messages
6,027
Re: 2000 350 Mag MPI won’t start…

Before you spend more money on parts, diagnose one step at a time. Get(or make) a spark tester and confirm whether or not you have a GOOD spark (blue is good, yellow is bad, nothing is worse. Makes a 'snap' sound). <br /><br />Reading the codes would also be a good first step.
 

newport dave

Chief Petty Officer
Joined
Nov 21, 2004
Messages
458
Re: 2000 350 Mag MPI won’t start…

First, disconnect the tach and retest. <br /><br />If that does not help, like Duna said, get a spark tester and check for spark. If there is none, do the Thuderbolt V trouble shooting procedure. It's easy and does not require a scan tool.<br /><br />I agree that you should check for trouble codes. This can be done easily with a paperclip and 12 volt LED light.<br /><br />Dave<br /><br />
tboltVmpi
 

Luna Sea

Lieutenant Junior Grade
Joined
May 20, 2002
Messages
1,069
Re: 2000 350 Mag MPI won’t start…

Guys, thanks for the replies, and I'll go easy with the either.<br /><br />Kind of wrote this in a rant yesterday, friends wrench friend asked if I used any boating forums for reference. So I felt I had to post something, just can't be specific enough I guess at this point.<br /><br />I'm gonna make another attempt out there on my mooring tomorrow. I still have the original coil that only didn't work when it was hot, that may prove useful for troubleshooting. And there's still a few ground's I can clean/wirebrush. And I'll see what I can do with the flowchart Dave posted. I have the type of spark tester that accepts a spark plug boot at one end and clips to the motor/ground at the other. That's the type to use? And now that I think about it can I use that type on the coil wire?<br /><br />Happy Boating...
 

Dunaruna

Admiral
Joined
May 2, 2003
Messages
6,027
Re: 2000 350 Mag MPI won’t start…

Originally posted by Luna Sea:<br /> I have the type of spark tester that accepts a spark plug boot at one end and clips to the motor/ground at the other. That's the type to use? <br />Happy Boating...
Perfect.
 
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