New boat with merc 5.7

[herrmanator]

Just purchased a new boat. My old boat had a mercruiser 3.0 (I beleive). New boat has a 5.7.

Is winterizing this engine the same as winterizing the old 3.0? Antifreeze in block, new gear lube,new oil, change filters?

I have done the old mercruizer a dozen times and just want to make sure I dont miss anything.

Also having a starting issue but before I ask questions on that I need to check a few things first. Spark from coil, spark from cap then plugs in that order. Tried to turn it over last night just putting starter fluid in the carb. Got one little flame but thats it. Originally thought bad gas because it had sat so long but it should have given me more reaction using starting fluid only if it had good spark.

 

[brian3127]

Brand new or new to you?

 

[Scott06]

Just purchased a new boat. My old boat had a mercruiser 3.0 (I beleive). New boat has a 5.7.

Is winterizing this engine the same as winterizing the old 3.0? Antifreeze in block, new gear lube,new oil, change filters?

I have done the old mercruizer a dozen times and just want to make sure I dont miss anything.

Also having a starting issue but before I ask questions on that I need to check a few things first. Spark from coil, spark from cap then plugs in that order. Tried to turn it over last night just putting starter fluid in the carb. Got one little flame but thats it. Originally thought bad gas because it had sat so long but it should have given me more reaction using starting fluid only if it had good spark.

There are more drain points on a 5.7 than a 3.0. You can use af in block but drain it first. Personally I leave mine dry and drained but that debate is like a which oil is best discussion.

Do you have a serial number for the engine so we know what version of the 5.7 you are working on? Would get an inexpensive spark gap tester and see if you have a good strong spark . In the stickies at top of mercruiser section is a troubleshooting guide for Thunderbolt ignitions assuming that is what you have.

 

[herrmanator]

Brand new or new to you?

New to me. Engine was new 2 years ago has 68 hours on it

 

[herrmanator]

There are more drain points on a 5.7 than a 3.0. You can use af in block but drain it first. Personally I leave mine dry and drained but that debate is like a which oil is best discussion.

Do you have a serial number for the engine so we know what version of the 5.7 you are working on? Would get an inexpensive spark gap tester and see if you have a good strong spark . In the stickies at top of mercruiser section is a troubleshooting guide for Thunderbolt ignitions assuming that is what you have.

Not off hand. I will check tonight when I climb into it to check and see if I have spark from the coil.

 

[Scott Danforth]

If you got a flame, you have spark

How long did the boat sit?

Carb or EFI?

 

[herrmanator]

If you got a flame, you have spark

How long did the boat sit?

Carb or EFI?

Yes the flame means spark however we did this several times and only got a little flame once so either it is intermittent spark or very weak spark correct?

It is a carb.

Boat sat pretty much all summer in the marina. I have some K100 coming today to add to the fuel. I am hoping it is just water in the fuel but the boat ran great until it didnt start at all so I am skeptical. I will have time tonight to check spark on everything.

 

[Scott06]

Yes the flame means spark however we did this several times and only got a little flame once so either it is intermittent spark or very weak spark correct?

It is a carb.

Boat sat pretty much all summer in the marina. I have some K100 coming today to add to the fuel. I am hoping it is just water in the fuel but the boat ran great until it didnt start at all so I am skeptical. I will have time tonight to check spark on everything.

Hook up a small gas tank to fuel line or use an outboard tank to test. Or dump fresh gas down carb should stay running if you dribble fuel down it if you have spark and its fuel related

Use a $10 spark gap tester to asses spark strength should be blue or white and jump at least 3/8"

 

[herrmanator]

Hook up a small gas tank to fuel line or use an outboard tank to test. Or dump fresh gas down carb should stay running if you dribble fuel down it if you have spark and its fuel related

Use a $10 spark gap tester to asses spark strength should be blue or white and jump at least 3/8"

How much fresh gas down carb?

 

[nola mike]

How much fresh gas down carb?

A couple of teaspoons. Don't waste your time on additives. If you have water in your tank, it needs to be physically removed. Do you have a fuel water separator?

 

[Scott06]

How much fresh gas down carb?

As Nola mentioned a couple teaspoons. I use an empty small food container to dribble it in a teaspoon or so at a time, you can keep it running this way if it is fuel starved but has a good spark.

Not to beat a dead horse but did I mention using a spark gap tester. One of the best tools for this point in diagnosis to point you towards fuel or spark being the issue ...

 

[nola mike]

As Nola mentioned a couple teaspoons. I use an empty small food container to dribble it in a teaspoon or so at a time, you can keep it running this way if it is fuel starved but has a good spark.

Not to beat a dead horse but did I mention using a spark gap tester. One of the best tools for this point in diagnosis to point you towards fuel or spark being the issue ...

I'm partial to a timing light initially. Doesn't tell you the quality of the spark, but if you're getting a steady flash you're likely dealing with fuel. Esp in an electronic ignition.

 

[Scott06]

I'm partial to a timing light initially. Doesn't tell you the quality of the spark, but if you're getting a steady flash you're likely dealing with fuel. Esp in an electronic ignition.

Yes has its place too but I had a outboard where you could see a spark on the plug, this was an old 2 stroke with little gap on the plugs. Was hard to start and would bog at mid range rpm then catch eventually at higher rpm. Both coils were DOA... the difference between old and new coils on the gap tester was dramatic and would have been really easy to see and prevented me from needlessly rebuilding the carb ...

With new coils the engine started instantly. Since then I took baseline readings on all my engines when running well. Then if an issue comes up can compare if spark is lost

 

[herrmanator]

A couple of teaspoons. Don't waste your time on additives. If you have water in your tank, it needs to be physically removed. Do you have a fuel water separator?

I do I believe have a water/fuel separator. I will remove that once I check for spark this evening IF I have spark.

 

[herrmanator]

Thanks for all the help fellas. I am a quality engineer and not a mechanic but I have a few things to try out and will post up here with results. The fuel down the carb is a good one and will do that tonight after checking the coil.

Much appreciated.

 

[nola mike]

Yes has its place too but I had a outboard where you could see a spark on the plug, this was an old 2 stroke with little gap on the plugs. Was hard to start and would bog at mid range rpm then catch eventually at higher rpm. Both coils were DOA... the difference between old and new coils on the gap tester was dramatic and would have been really easy to see and prevented me from needlessly rebuilding the carb ...

With new coils the engine started instantly. Since then I took baseline readings on all my engines when running well. Then if an issue comes up can compare if spark is lost

That's a bit different though. I said initially; if it isn't starting and you're getting timing light flashes, I'll move to fuel. I wonder what a poor man's gap tester would be--old plug that you really widen the gap on? On my outboards/small engines I usually can't be bothered to find my gap tester...
@achris turned me on years ago to using a timing light on a plug wire when under way to detect intermittent misses on one/some wires. Amazing how obvious the miss is on a light, even if you can't hear/feel it. I was surprised that you can see a miss even at very high rpms.

 

[Scott06]

That's a bit different though. I said initially; if it isn't starting and you're getting timing light flashes, I'll move to fuel. I wonder what a poor man's gap tester would be--old plug that you really widen the gap on? On my outboards/small engines I usually can't be bothered to find my gap tester...
@achris turned me on years ago to using a timing light on a plug wire when under way to detect intermittent misses on one/some wires. Amazing how obvious the miss is on a light, even if you can't hear/feel it. I was surprised that you can see a miss even at very high rpms.

You can google homemade spark gap tester and find a bunch of ways to coble one.

If you have a system that works for you stick with it, I'll try the timing light next time. Just really stuck out at me on a inexpensive tool how different the spark looked on a poorly performing system vs when I set up the TBV when I repowered.

 

[herrmanator]

I tested things tonight and found I have no power going to my coil. There is a safety switch? My cousin told me about I need to check. On left side of motor by shift cable. Apparently it can be set not right and kills power to the coil. With no voltage at the coil I have to assume this is maybe the problem? Anyone dealt with this?

 

[Scott06]

I tested things tonight and found I have no power going to my coil. There is a safety switch? My cousin told me about I need to check. On left side of motor by shift cable. Apparently it can be set not right and kills power to the coil. With no voltage at the coil I have to assume this is maybe the problem? Anyone dealt with this?

There is a man overboard switch on some models usually a red toggle switch on the shifter. It cuts ignition of when the key is in run and the switch is tripped.

I think during start the ignition system is feed off the starter lug during cranking. On my boat if the MOB switch is tripped the engine will start and then die when key comes off start to run position. I think there is also a fuse in the helm harness on ignition. Need to get a Volt meter and trace out if you have 12 v at the key.

Also no one on this threads know which 5.7 you are working on as merc only made the 5.7 for like 40 years... serial number or at least model and approx year would help

 

[herrmanator]

Last week was pretty crazy and the weekend was spent at Lake George in New York. My cousin jumped the switch and it started. Have boat at a guys house to adjust the switch. I still dont have the S/N but will get that. This is not the MOB switch at the helm. Cousin calls it a switch, might not be a switch. He sent me a picture but had to reset my phone so lost pictures.

We have it figured out. I will post up here in a few days after its fixed with the proper terminology.