1993 OMC 4.3 with Cobra Drive

I have just a few questions about my rig that has served me so well for 18 years. On the water last weekend the motor quit while cruising at 3,000 RPM, after running 30 minutes (first time out this season). The marina diagnosed the problem as the ignition coil. I assumed the diagnosis was much worse, and the engine would not turn over after it quit. After a 1-hr tow back to the launch, it turned over but would not fire. This was the first time the motor has seen a wrench, other than the regular maintenance I have performed myself all these years. I read with interest all the threads in this forum. I run in fresh water, and my boat is dry stored in a barn (trailered each use). So long as I keep a fresh thermostat and water pump impeller, it runs perfect at 160-degrees. I have never done any maintenance to the risers/manifold on this motor.

Is there riser/manifold maintenance I should do?
It's hard finding SAE30 motor oil, so I run 10W40. Is this bad for the engine?
I use the StarTron fuel treatment for the E10 gas (89 octance) I use in the engine, is this sufficient or is there a better product?
I'm considering new belt/hoses this season (all are original) and see some hoses are obsolete on this site. Any recommendations for a source of good quality hoses?
Is there any other preventative maintenance I should perform on this 18-yr-old rig?
Except for this recent ignition coil, everything else is original.

I appreciate the time/consideration.

I don't know where you live but wally world has straight 30 is is all i ever used.

I tell ya the coil went can happen. Keep the points clean every year sand em.

The mani on my boat only used in salt water is original the riser is the second one.

I think leave it alone just keep doing what your doing. I don't add nothing to the gas.

Last couple of years i ran the carb dry and stored it. Very little gas if any in the tank.

Every couple of years you could suck the gunk off the bottom want the post how i will re post it.

Not wanting to turn over until it got cold doesn't seem right to me.

Don't suppose you happened to notice the engine temperature at the time it stopped? Could it have been running way too hot, and simply momentarily seized?

Have you rechecked the pump impeller?

Bruce.

I always keep an eye on the temp gauge, and had removed and checked the impeller the day before I ran the boat (the OMC outdrive makes it so easy, compared to the volvo/penta which I need to remove the floor and backsplash of the boat). The temp gauge read 160 when the motor quit. I'm sure it was not an over-heating issue. I too don't understand why it wouldn't crank right over, and why an hour later it cranked but no spark. The marina is a reputable Four Winns dealer and brought the motor up to operating temp after the repair. Tomorrow I will in-water test it.

George

Maybe the throttle was not fully in neutral it won't crank. Wiggle the handle.

No spark latter at the dock but it was in neutral, but the dead mans switch was pulled maybe. Thats why it would crank and not start ???

All maybes. Maybe i'll wake up tomorrow and i'll have the body of a 20 year old.

The problem turned out to be the igniition coil. Your diagnosis of why it wouldn't immediately crank over is likely correct (throttle not completely in neutral). An earlier post suggested sanding the points once a year. The engine has electronic ignition, so it has no points. Interesting to me the coil would fail like that all of a sudden. Another buddy suggested that with immediate loss of spark while running fouled or locked up the cylinders, and it wasn't until an hour later and a tow to the dock that everything had a chance to vent. 18 years of trouble-free usage has me spoiled. It's a terrific engine that should give many more years of service. I'm replacing the belts and houses for good measure, 18 yrs is a long time for those.

Sorry about the points sanding item i posted. I should have looked at the year. If all it was is a coil your lucky.

Good luck and go boating, i'm getting my boat wet the first time this year today.

Update and lesson learned. My original symptom was the engine quit while cruising at 3,000 RPM. This was my first time out this season, and I had changed the outdrive gear oil in the Fall before winterizing. I am certain the gear oil was full, and it was filled properly (with a pump in the 2nd hole from the bottom). When the motor quit it sounded bad, like metal coming together. The motor would not even turn over after it quit, and the battery was good. After a 1-hour tow back to the launch, the motor would turn over, but not start. My marina mechanic diagnosed this as a bad coil. He ran the motor he says on a hose to operating temp, and said I was good to go. The following weekend I used the boat, idled 100 yds from shore and my son mentioned he heard a high pitch whining noise. I took the boat out of gear and revved the engine. No noise. I decided to idle back to the dock, and that's when the upper gear case seized. Back home I checked the dipstick top of the outdrive. Dry. The marina mechanic said the unit was low on gear oil. Said the seal between the gimbal bellows and the upper gearcase failed, allowing gear oil into the bellows and failing to lubricate the upper gear set. The bevel gears are purple (from heat) and I'm spending $2100 on a new upper. While apart, I'm also have the lower inspected and sealed. As a normal maintenance item on a rig that is 18 years old, should I have had a mechanic replace all the seals on the outdrive?

Whoa, slow down. You're spendin $2100 on a new upper? You can get a complete new SEI sterndrive which is essentially an aftermarket Mercruiser for around 2k with a 3 yr. warranty. It's a conversion kit. And you'll be rid of that OMC dinosaur. That's what I would do. You're looking at almost 3k parts & labor if u have him reseal that whole drive. Not worth it IMHO.

I've looked at the SEI web site, and there are a lot of hidden costs that will easily push the conversion to over 3 grand. The drive is 2K, the install kit another $500, plus you need a new prop for another $400 and maybe a new shifter and cables for another $500, then there's installation....
I would be asking myself if the 18 year old boat is worth sinking that kind of money into at this stage, whether it be for either the repair or the conversion.

If it were me, I'd be looking for a good used upper drive for somewhere in the $500-1000 range, a gasket set for $20 and be done. Fleabay is full of them.
http://cgi.ebay.com/ebaymotors/OMC-...at_Parts_Accessories_Gear&hash=item2a1172cf01
http://cgi.ebay.com/ebaymotors/OMC-...at_Parts_Accessories_Gear&hash=item3cb8dd2639
http://cgi.ebay.com/ebaymotors/OMC-...at_Parts_Accessories_Gear&hash=item3cb8dd2e4a
http://cgi.ebay.com/ebaymotors/OMC-...at_Parts_Accessories_Gear&hash=item3cb8dd361c
http://cgi.ebay.com/ebaymotors/OMC-...at_Parts_Accessories_Gear&hash=item19c6379267
http://cgi.ebay.com/ebaymotors/OMC-...at_Parts_Accessories_Gear&hash=item3cb8dae218
http://cgi.ebay.com/ebaymotors/4-3-...at_Parts_Accessories_Gear&hash=item2a1183745e
http://cgi.ebay.com/ebaymotors/OMC-...at_Parts_Accessories_Gear&hash=item5199a98801
http://cgi.ebay.com/ebaymotors/USED...at_Parts_Accessories_Gear&hash=item20b76caedd
http://cgi.ebay.com/ebaymotors/OMC-...at_Parts_Accessories_Gear&hash=item3cb7648e42
OK you get the idea...
Enter "Cobra Upper" in the ebay search box

400 for a prop? I paid 400 for a whole boat and trailer.

I also paid 3 hundrend for the whole boat and trailer.

3 grand for a drive. I'll sell my boat and trailer for 3500 right now i'm tired of it anyway.

Chiefalen,

You pointed me in a direction, but I can't find the thread. 4.3 OMC has a sagging power tilt/trim symptom. You mentioned a valve might be available at Napa. Will you repost?

Thanks !

George

I don't think it was me.