2005 50hp Won't run [ Edited ]

[Boater_Matt]

Hi folks, Thank you for any help and suggestions

My E50DPSLOR suddenly stopped running this summer after some electrical issue in the spring. Couldnt diagnose electrical issue but found workaround (have to have all wires off the battery but motor wires to get it to start).

But now the motor only starts when I take out the top plug.

• Both plugs have spark
• Both are getting gass, no water on plugs, ran ethanol free past two years
• Plugs replaced
• Fuel filter replaced
• Battery replaced
• Wont run with top plug in--have to pull it out--plenty of air shooting out of top plug hole
• Was able to check 1 fuse (maybe the only one?) and it's good
• All visible wires without greater disambly appear to be in good shape

Thank you for any help you can offer, the only certified e tech technician in my area is $100hr!

[Boater_Matt]

Any ideas? Anyone?

[baddog1016]

If it has spark, fuel and compression, it has to run unless ignition is out of time and that can only happen if the flywheel has moved on the crankshaft. Are you saying that it runs if you pull the top spark plug out? What you had to do to get it running when it worked makes me think it wasn't/isn't cranking fast enough to start. If it does start with one plug out I'll bet what I just said is the problem. I don't know how fast this engine has to crank to start but my 2000, 225 and a '93 200 that I have worked on both need 250-300 RPM to start. I wasted a lot of time on the 225 because it sounded like it was cranking just fine but it wasn't. 

[Boater_Matt]

Thank you for the thoughts Baddog. I just ordered a compression tester so we will see about compression.

I don't think anything has happened to cause the flywheel to move on the crankshaft. If my EMM is failing couldn't that mess up the timing?

It cranks very well and fast so I don't think that's the issue.

I did a new test the other day:

As I had said, it only runs when I pull the top plug. So I tried pulling the bottom plug, leaving the top in. Does not start.

A friend suggested that means the top cylinder is bad. Could be a blown gasket.

Could that be it? The plugs are very dark with soot.

[baddog1016]

It could mean the top cylinder is dead. Compression test will answer the question. My experience with these engines is limited, I do not know what the EMM failure modes are. I do know how engines work, though.

Did the engine crank significantly faster with the bottom plug out than it does when the top one is out?

When the engine did run after you did the disconnecting you had to do, how did it run? My bet is that whatever was causing the issue that made the engine not start unless everything was disconnected has gotten worse and the only way I can think of to explain the fact that it will start without the top plug in place is cranking speed. It just occured to me that if the no start is bad compression in the top cylinder than plug in or out shouldn't make a difference.

[Rickmcd53]

Swap the two injectors around and see if it then runs on cylinder 1 with #2 plug out.
It sounds like #1 injector is giving too little or too much fuel. With good compression on #1 cylinder the #2 cylinder cannot make enough power to get past the compression on #1 cylinder but will run with no compression on #1.

[baddog1016]

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@Rickmcd53 wrote:
Swap the two injectors around and see if it then runs on cylinder 1 with #2 plug out.
It sounds like #1 injector is giving too little or too much fuel. With good compression on #1 cylinder the #2 cylinder cannot make enough power to get past the compression on #1 cylinder but will run with no compression on #1.

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I like this idea. 

[Boater_Matt]

Finally got around to doing the compression test

#1 gives 75 psi

#2 gives 100

I don't know if I'll be able to try swapping the injectors anytime soon as it looks a bit involved and I'm up in maine trying to work on this thing without a garage so weather/light/frozen battery is an issue.

Based on this difference in compression, is it certain I have a bad cylinder? Or  head gasket?
Or could it sill be an injector issue?

Thank you

[BluewaterBill]

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@Boater_Matt wrote:

Finally got around to doing the compression test

#1 gives 75 psi

#2 gives 100

I don't know if I'll be able to try swapping the injectors anytime soon as it looks a bit involved and I'm up in maine trying to work on this thing without a garage so weather/light/frozen battery is an issue.

Based on this difference in compression, is it certain I have a bad cylinder? Or  head gasket?
Or could it sill be an injector issue?

Thank you

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25# difference is excessive and an internal inspection of the piston, rings, and cylinder wall is needed.

[baddog1016]

The difference in compression is not good but I don't think the bad cylinder is so bad it will make it not run. Also, won't it run on one cylinder iwth the spark plug out of the other? If everything but the compression was good it would start regardless of the low compression in that cylinder, when the spark plug is out there is no compression in that cylinder. Hear me now, believe me later, you need to make sure the engine is cranking fast enough.

Like Bill said, go over all of the connections. I will caveat everything I saywith except for 3.5 & 4 HP outboards my experience is with a 2000 Ficht 225 and a circa 1994 200 carbed engine. I own the 2000 engine and had a lot of trouble getting it started because it wasn't cranking fast enough even though it sounded like it was. I even sent my EMM to DFI to be told there was nothing wrong with it. While they had it I found out about the crank speed thing. How close is your battery to your engine?

I charged my batteries, cleaned those connections, replaced my isolation switch and cleaned the connections at the engine. Starting was better but if the boat sat for a couple of weeks I needed my jump box to get it started. I started thinking I had a bad cables and was checking those out when I had the big DOH! moment. There is a junction box in a locker at the transom that's hard to see and that's where the bad connection was. Cleaned those connections and my starting problem was over. I was in thw Auto business for 35 years and time and time again I have seen where "careful visual inspection" is all it takes to find a problem.