Newly rebuilt 2300SCR engine doesn't run at all!

[bkgoodman]

New long block - new thermostat, thermostat housing, impeller, elbows, raw-water pump. Manifolds inspected and pressure checked (all good), outdrive had complete seals and bearings replaced, etc.

Boat ran GREAT for the first 2 or 3 hours (though almost exclusively displacing). Then a had a temperature issue (see other thread).

I then displaced around all day - accumulating only a couple more engine hours - had no problems.

The next day I fired here up to displace around a bit. Was about 15 minutes from the marina (displacing, inside the no-wake zone), I throtled up a tiny but (not even trying to push it on-plane) - and the engine just quit. Wouldn't restart. Cranked fine, but never started.

Mechanic has been working on it for about a week or so - called me and said he had no idea. It cranks fine, fuel is good, carb is newly rebuilt, clean as a whistle and looks like it's fine, timing is checked and good, plugs are correct, etc. etc. etc. but won't start at all!

Speculation has been around a few things: getting spark, but maybe its too weak.

• Ignition coil? Maybe - but this usually manifests itself in either "spark or no-spark". Not weak spark - or maybe even "spark" when it's cold, and "no-spark" when hot.
• Ignition Module? Again, usually works, or it doesn't.
• Bad wiring to ignition coil? One of my mechanics suggested (that the other mechanic) try a directly connecting battery to coil.

My issue is that my boat is an hour (inland) from the mechanic who fixed it - and I have no trailer. So I could pay to haul it (two ways) to him (who can't do any on-the-water trial) - or continue to pay the other guy (at the marina) who can't figure out the issue after 4 hours.

All I can say is, if either of my mechanics were actually as better than the other mechanic as they say they are, I'd have a working boat by now! :-(

[pascavone]

pull the spark plug yourself, and check for water droplets.

check you engine oil for milky color.

if ok,

then, change the fuel strainer, and fuel pump. try a can of quick start.

then,

pull a spark plug wire, then hold it close to the block and see if your get a arch. you need someone to bump the engine on the starter.

sounds like water in the engine.... but check and let us know.

[ss3964spd]

It needs compression, fuel, and spark - that's all. If compression and fuel have been verified all that's left is spark.

He needs to pull a spark plug out, leave the wire connected, ground the threads to the engine block, then crank it over. If there's no spark the mech needs to check for 12V on the + post of the coil when the ignition switch is in the "Run" position. If that's there the most likely culpret is the ignition module.

There's also the possibility that the kill switch at the helm was accidently tripped, or that the oil pressure sending unit is bad.

Dan

BTW, he cannot check/verify the timing unless the engine runs.

[bkgoodman]

I think he checked the timing by cranking the enigine (I assume).

There is spark, and very good compression. He did verify the fuel was good. (At first, they said water in the fuel. I haven't run the boat since before the Ethanol days, so it doesn't have a water separating filter on it - so I think they put one on there. But that issue's been addressed, and the fuel now looks good).

I think the speculation is weak spark - not enough to cause igniton. What would cause that?!

[ss3964spd]

He cannot check the timing by simply cranking the engine. The engine MUST be running. If he is telling you that he can verify the timing by just cranking the engine I respectfully submit that you need to find another mechanic.

If he has verified that it has spark when cranking and he suspects weak spark, the coil could be bad or the module. Even the electrical connections to both could contribute. There is also a simply testing device that goes between a plug wire and a plug that lights up when it sees voltage on the plug wire. If it lights dim then the ign system is weak but it still don't tell which component is bad.

Also, I assume that they've been cranking and cranking this thing trying to get it to start, using the choke, pumping the gas. There is a possibility that the plugs, even though they are new, are now so fouled with gas that they won't fire.

Dan

[ss3964spd]

Another thought: If he thinks he can check the timing by cranking the engine, is there a possibility that he adjusted/set the timing while cranking the engine? If he did the timing might now be so far off that it won't start.

[bkgoodman]

Answer was: (Drum roll please...)

Cracked rotor!

I didn't think it was going to be it - but he found a tiny hairline crack in the rotor - and that was enough to do it!

Diagnosis was: Got good, consistent spark out of the ignition coil, but got weak, intermittent, or NO spark to the spark plugs. Inspection of the cap and rotor revealed a hairline crack in the plastic part of the rotor.

[pascavone]

i love a happy ending! hope for us all!

[shrew]

Very nice!! And a relatively cheap fix.