Runs and tests fine out of water. Runs rough, stalls out and misses when in water.

[ghallof]

Hi All,

OMC 5.7 Cobra Chris Craft 245 Limited. Out on the water a couple of weeks ago the boat began run poorly. Missing, Stalling during shift. No power then power. Use trim tabs or trim and it would appear draw power away from the ignition. Let off either and power would come back. This lasted about 30 minutes or so. Since then I have been out a few more times and the problem appeared to be getting worse. Came back and starting doing some research. Went down the ESA, Tune up kit (Cap, Rotor, Condensor, Points) Ignition Coil path. Replaced all with new, took the hail mary approach and still the issue continues.Continued my research.. Resistive wire, checked new ESA, checked interrupter switch, checked over stroke switch, checked adjustment on all shift cables. Here is the KICKER...Out of the water all of the above checks out fine. Boat runs fine. Interrupter and overstroke switches work and test out great while running. Trim and Trim Tabs do not rob power from ignition when operated. As soon as I put the boat back on the water....PROBLEM IS BACK again

 

[HT32BSX115]

Use trim tabs or trim and it would appear draw power away from the ignition. Let off either and power would come back.

Howdy,


Welcome aboard,


Sounds like an electrical problem that may be related to loose/corroded connections. This could be in either ground or power connections. The power trim motor is a "high-draw" device and it's usually hard-wired to the battery and independent of the main electrical system. If your battery and ALT are good you may have a bad ground connection.....

Sometimes switches become defective, crimped connectors, circuit breakers and fuses become corroded or loose.

I would start at all the battery connections and work through all of them.

The OMC service manuals have pretty good troubleshooting sections.


Regards,


Rick

 

[ghallof]

Hi Rick,

Appreciate the reply. I am curious as to why everything checks out fine, motor runs fine when out of the water. Put it in....and it seems to cause the issue to occur. Perplexed at best.

I just found the trim sending unit on the drive to be shot. Badly corroded and non functional. Not to mention once I traced the two wires through the engine compartment it looked like someone (previous owner) decided that some re-wiring of it needed to be done. I disconnected it completely.

 

[bruceb58]

There was a person on here once that was having the same issue and it was caused by his loose flappers clogging the exhaust. When out of water there was a little less back pressure so the exhaust flowed a little freer and he didn't have the issue.

If you really want to get the ESA out of the equation, just unplug it. Just know that if you try to shift out of gear, you may have to turn the motor off.

 

[vinnie1234]

Another difference when in the water vs out of the water, is that the engine is under load. Sometimes a weak spark will cause the issue. If the ignition system is tuned, I would first check the alternator belt tension, then check voltage at RPM. If this checks out then go for the loose/corroded connections.

You also could have a fuel delivery problem. If there were a blockage in the carb, it may seem fine on the muffs, but under load is a different story.

 

[ghallof]

Thank you for the feed back. I have gone through everything as far as a visual inspection. Next up is to pull the main ground and main positive cable paying close attention to the ground cable at the motor. Cut the shielding back and make sure its in good shape. Clean up positive at both ends. At the same time. Dropping off alternator to have it bench tested by a reputable local electric motor shop. Points, cap, rotor, condenser, ignition coil are all new and all is set correctly and tests (Albeit out of water) appropriately. Wires in good shape. Plugs new at begin of season. I think that should cover the basics to start. Let me know if i missed anything glaringly obvious.

 

[bruceb58]

I have a question. I was under the impression that it doesn't even idle in neutral when its in the water. Is that the case?

 

[ghallof]

Hi Bruce,

From a dead engine stop. The boat will start and idle. If I am lucky on a good shift. It will hold idle also. All of the rough running, missing and such only occur in the water. All systems test and run well on land. Just had the alternator tested this morning and it checks out fine. ESA, Interrupter switch, overstroke switch all test out fine.

 

[vinnie1234]

Did you set the gap on your spark plugs when you installed them?

 

[Maclin]

Are you sure the dwell is in spec and the initial timing is in spec? Had to ask. Also, you might describe how the timing was set after the dwell was set. Also triple check spark plug wires are hooked up in correct firing order.

 

[bruceb58]

Hi Bruce,

From a dead engine stop. The boat will start and idle. If I am lucky on a good shift. It will hold idle also. All of the rough running, missing and such only occur in the water. All systems test and run well on land. Just had the alternator tested this morning and it checks out fine. ESA, Interrupter switch, overstroke switch all test out fine.

OK. I didn't understand your initial post then. Forget what I said about the exhaust.

 

[craigvalk]

Check your fuel filters?

 

[ghallof]

No Title

UPDATE.... I think I found the problem. I haven't confirmed this yet. Hopefully Ill be able to test out fully tomorrow. I ;have spent the past couple of days going through everything. Electrical, Ignition, Fuel, Shift linkage..you name it. I kept coming back to wondering why in the water vs. out of the water. Even though load vs. no load makes sense to me, I just couldn't get passed that this was an Ignition problem based on the sound of the motor and behavior when the problem happened. .

I have attached two photos....I'll try to explain based off of the images.

Image 1 = two red arrows
Image 2 = one red arrow

So while I was testing everything in my driveway with muffs and the engine cover up. I noticed that the starboard side through hull exhaust had a small leak. The old transom exhaust, which you can see in image 1, would catch the water drip from above. Didn't look like a big deal. I didn't give it another thought. Today I went over to a friends marina and they allowed me to use one of the ramps to test in the water. Backed the trailer down. Fired her over on the trailer and started going through some shift linkage testing. I noticed the leak again. This time I started to pay a bit more attention. Now that the boat was on the steep angle of this particular ramp. The water was dripping into a different area. I was running the throttle up fairly high trying to get the failure to occur. I did this for about 5 or 10 minutes...nothing. Boat ran great. Still idling at this point. Decided to run the throttle up again just to be sure....BAM...sure enough, coughing, spittin, sputturin, missing like crazy, boat vibrating and end the end stahl. Tried it again same thing.

Took another look at the engine compartment and noticed more water from the leak. (Image 1 left arrow shows where the leak was coming from..New clamp on now) The right arrow shows location of wires, the wire sorter bolt and two ground wires someone decided to hang off the wire sorter mount. Image 2 is a close up of the wire sorter bolt head where the grounds attach. Keep in mind the wires were right up against this bolt prior to the picture. Anyway...water on the ignition wires...water on the ground wires...and water on the bolt head. Look close at image 2. One of the two ground cables is simply stripped and bare wire behind the bolt. A number of the strands are/were hanging out.

Theory at this point.... Ignition wires at wire sorter deteriorated, or wire sorter has pinched into silicone. Water sprays on surfaces. Ignition wires arc. Not only do they arc. They arc directly onto the two ground cables.

Thoughts???