Help with 5.0L EFI boggy

Muzbomb

Cadet
Joined
Jul 3, 2020
Messages
28
Fixed broken wire and I got it started running for about 1min then it died and will not start but I noticed when I try to start it there is an arc still at the coil and positive terminal when it is trying to turn over???
 

alldodge

Moderator
Staff member
Joined
Mar 8, 2009
Messages
43,318
Your coil is leaking and needs replaced from the sounds of it. If there is a crack then its gone
 

Muzbomb

Cadet
Joined
Jul 3, 2020
Messages
28
So I bought a new coil they is nothing open on a weekend in my town so i manage to find one but it was not a marine merc part it was from a 305 GM engine i hooked it up and boat fired right up seem to run good for a bit then i touch the coil to distributor cap wire at the distributor on the wire not the boot part and got a shock?? Then I noticed few mins after the new coil had cracked. So not sure. I know it is best to use only marine parts and I will get one Monday but just wanted to see and not sure why I would get shocked?
 

alldodge

Moderator
Staff member
Joined
Mar 8, 2009
Messages
43,318
The coil should be the same, have not found marine specific coil only if they have internal or external resistance, and in your case this is not an issue. It may not be the coil, it may be the wire and boot. Unable to see what you can
 

Muzbomb

Cadet
Joined
Jul 3, 2020
Messages
28
Ya I am going to get a new coil and plug wire kit Monday along with new spark plugs. This coil was pretty cheap 34bucks Canadian. Going to get all that done Monday and will see only thing left in ignition will be the ignition sensor in the distributor I think. I am convinced that my issue is not fuel anymore though.
 

Muzbomb

Cadet
Joined
Jul 3, 2020
Messages
28
I was looking closer and Found the crack in the plug wire going from the center top of distributor cap to top of ignition coil. It is right at the end of the distributor just after the boot on the wire its self. So hopefully new ignition wires, coils and spark plugs will cure this problem.
 

Muzbomb

Cadet
Joined
Jul 3, 2020
Messages
28
From what I have found and see I am going to go with the ACMR43LTS spark plugs have the .45 gap that from what I have researched I need
 

Muzbomb

Cadet
Joined
Jul 3, 2020
Messages
28
So just as I thought nothing In stock here so I got new spark plugs, coil wires and a new coil. Should all be here Thursday will have in boat hopefully all Thursday and see what happens. Also while doing spark plugs will do compression test. I know you are suppose to have engine warm for a compression test I believe but can’t really do that as it won’t start with out a coil. When I get the parts should I just to the coil and plug wires first then see if it runs warm it up and then do the plugs/compression test or can I just do it cold?
 

alldodge

Moderator
Staff member
Joined
Mar 8, 2009
Messages
43,318
Nothing wrong with a cold compression test. If numbers are good, then no need to go further. Once warmed up it will only get better
 

Muzbomb

Cadet
Joined
Jul 3, 2020
Messages
28
Ok so got some Cold compression numbers and go new plugs in just waiting on new plug wires to arrive still. I think numbers look good for a cold test.
  • #1 cylinder: 145 psi
  • #2 cylinder: 145 psi
  • #3 cylinder: 145 psi
  • #4 cylinder: 145 psi
  • #5 cylinder: 140 psi
  • #6 cylinder: 145 psi
  • #7 cylinder: 145 psi
  • #8 cylinder: 145 psi
 

Muzbomb

Cadet
Joined
Jul 3, 2020
Messages
28
Ok so got the new plug wires on and boat would not start then got the new coil on and boat fires right up on ear muffs sounded great. Then got it out on lake and boat started right up and idled great. Got out on water warmed motor up and then put hammer down boat shot right out of water did this several times and boat ran great!!! On way back to dock slowed right down to about 10mph and was coasting there for a bit and then boat started to idle down and then rev up and gave it a little more throttle seem to clear up a bit then slowed down again and as got close to dock and boat started doing it again rev up and down then died and would not start nothing no cracking nothing?? Got to dock Loaded boat up and got home. I put boat on ear muffs and noticed that coil wire on top of the coil had half come off and was just sitting on top of coil so...... this makes sense now why there was no power at the dock when tried to restart And nothing. But would this be why it was idling up and down too?
 

alldodge

Moderator
Staff member
Joined
Mar 8, 2009
Messages
43,318
I would install a fuel pressure gauge and leave it on during these times, I'm thinking its a fuel issue
 

Muzbomb

Cadet
Joined
Jul 3, 2020
Messages
28
Well boat ran amazing on the lake no issue at all. After fixing coil wire, taking TEE out of line and changing out to the anti Syphon valve. The anti syphon valve was for sure the fuel issue I installed a clear fuel line from tank to filter just so I can see and with other check valve on the fuel line would not stay full I think that check valve I had in there for temporary was not good soon as I installed the correct anti syphon valve and turned key on the line filled and stayed full and same while running boat.
 

Muzbomb

Cadet
Joined
Jul 3, 2020
Messages
28
Thanks for your help and info alldodge!!! Boat ran amazing once again today was out 6hrs.
 
Top