2006 340 8.1 Starting Problems

J

JPringle

Member
Sep 9, 2016
59
Florida
Boat Info
2006 340 Sundancer Sportsman
Engines
Twin 8.1 Horizon
The port engine was working fine one day and now won't start the next. The engine will turn over, but there is no spark. I noticed the 90 amp fuse at the starter solenoid was burned so it was replaced. I've replaced the crank sensor, switched the ECM from the good motor, new plugs, new plug wires and still nothing. Any Ideas?
 
JPringle said:
The port engine was working fine one day and now won't start the next. The engine will turn over, but there is no spark. I noticed the 90 amp fuse at the starter solenoid was burned so it was replaced. I've replaced the crank sensor, switched the ECM from the good motor, new plugs, new plug wires and still nothing. Any Ideas?
Click to expand...

Please do not take this the wrong way but swapping the ECM is not necessarily a good idea. While you already did this I would advise against it because if something burned out the ECM then plugging in the other may only lead to 2 times the replacement cost when you burn out the other one. It would be better to plug in a scanner/computer to see if the ECM is alive and responding and this is what I would do next.

-Kevin
 
SeadawgVB said:
Coil on plug on the 8.1 = 8 coils per motor. I don't think they would all go bad at the same time. I would investigate the burned 90 amp fuse, did it just look bad (which is suspect enough) or did it test bad.
Click to expand...

New fangled technology :)
 
So coming from the car world, with coil on plug you need a scope to see what's going on. Is it a 2 wire or 4 wire arrangement?
 
KevinC said:
Please do not take this the wrong way but swapping the ECM is not necessarily a good idea. While you already did this I would advise against it because if something burned out the ECM then plugging in the other may only lead to 2 times the replacement cost when you burn out the other one. It would be better to plug in a scanner/computer to see if the ECM is alive and responding and this is what I would do next.

-Kevin
Click to expand...
I understand... I switched them back and the original engine started (to great relief). A mechanic was there with a computer, but couldn’t figure it out. Looks like I’m going to call a different mechanic...
 
SeadawgVB said:
Coil on plug on the 8.1 = 8 coils per motor. I don't think they would all go bad at the same time. I would investigate the burned 90 amp fuse, did it just look bad (which is suspect enough) or did it test bad.
Click to expand...
It was burnt to a crisp! Starter wouldn’t work until I replaced it.
 
Was it tight? I just replaced the same fuse on both of my 496. It was loose and should be tight. It obviously got hot as the little plastic cap on the on side was melted. My Merc Service guy said if it isn't tight - and to make it worse add a little corrosion - causes poor contact which makes it get hot from not being able to carry the required amps.
 
Korkie said:
Was it tight? I just replaced the same fuse on both of my 496. It was loose and should be tight. It obviously got hot as the little plastic cap on the on side was melted. My Merc Service guy said if it isn't tight - and to make it worse add a little corrosion - causes poor contact which makes it get hot from not being able to carry the required amps.
Click to expand...
It was tight, but maybe just corroded. I was more concerned if it wasn’t strictly due to corrosion, what else would’ve caused it?
 
Update... Mechanic came out and went through every sensor with a multimeter and found one had a bad ground wire. Fixed that and motor works just fine. First mechanic said I needed a new engine. Go figure!
 
JPringle said:
Update... Mechanic came out and went through every sensor with a multimeter and found one had a bad ground wire. Fixed that and motor works just fine. First mechanic said I needed a new engine. Go figure!
Click to expand...
Yep. Gotta love some of them service folks. Once had an ac unit at home go bad. One guy came out, said " it's 12 years old, need to replace unit". Hit a second opinion, next service company said, bad reversing switch, have it up n running in 10 minutes. $59.00 later, it is fixed a ran with not issues for 5 more years b4 compressor went. Always get a second or even third look. Pays off.
 
8.1's do have heat sensors in the exhaust manifolds that are tied into the computer system. If cooling water to the system is not adequate, the manifold will get too hot and the sensor will set the engine in limp mode before things get too ugly (at least that's the plan).
 
You must log in or register to reply here.

Forum statistics

Threads
113,183
Messages
1,428,126
Members
61,091
Latest member
dionb
Back
Top