3.0 Mercruiser turns over but won't fire

[LakeTravisAlpha1]

I tried to start my '95 Mercruiser 3.0 LX Alpha One #F452165 today. It hasn't been started in eight years but did run on the trailer the last time I tried it. A few days ago I changed the oil which was surprisingly clean, pulled the plugs which too were clean and in good shape, sprayed the carb with cleaner, installed a new battery, put fresh gas in along with a can of Sea Foam and this afternoon changed the drive oil.

The carb was / is dry as I posted in a previous post so today I primed it with both gas and carb cleaner. It would turn over but other than that, made no sign of it wanting to fire off, no sputtering, no death rattle. I noticed none of my gauges now work either. There is a red fuse button on the engine that appears to be stuck in the out position as I can't reset it but am not sure it even does push back in.

I've read the long list of possibilities that could be wrong, everything from a bad tach connection to ignition switch but I don't have a clue where to look first. The Tilt / Trim works now as well as the Bilge pump, albeit it now sounds like an air horn, but the fact that all of the gauges are dead makes me think it's not getting a spark.

I have a mechanic buddy that said he would try and make it out and have a look and I'd like to at least contribute something other than "it won't start." What would be the first places to start looking? It started and ran the last time I tried it years ago so I can't imagine it being out of timing from just sitting.

 

[Fun Times]

If your shift/throttle control handle has this feature, be sure the ignition lanyard safety kill switch is up in the run position. Be sure to toggle the switch a few times to help ensure it is up/on for how your safety switch is designed. On some models the safety switch being off could keep the gauges from powering up. http://www.bing.com/images/search?q=mercruiser+ignition+lanyard+safety+kill+switch&FORM=AWIR

Sometimes the red 50 amp circuit breaker takes some effort to push back in when tripped but it may be fine since the engine cranks over.

At this point since the gauges don't move you do have an electrical problem though and not necessarily an engine running problem yet so things like engine timing shouldn't be an issue....Yet.
But with all the carb cleaning and sea foam added all at once, the engine "may" have a hard time starting due to possibly flooding the carb, cylinders and your new spark plugs.

I primed it with both gas and carb cleaner....Added fresh gas with a can of Sea Foam

 

[LakeTravisAlpha1]

Thank you Sir. I should clarify, I didn't prime the carb with gas and carb cleaner at the same time, rather just a small shot of gas then crank it until the starter and battery fatigued, wait and repeat. I did this maybe three times over a thirty minute period. Then after waiting maybe 30 minutes I tried the carb cleaner once, being concerned I wasn't fixing an explosive cocktail. The Sea Foam I had already added to the new gas in the tank.

It does have a lanyard and switch which I connected. I may go pull the plugs and see if they're wet. Now I did spray Liquid Wrench in the spark plug holes last week when I pulled, inspected and re gapped the the old plugs to 0.035 which btw looked new, as I was concerned the cylinders had seized.

 

[Alumarine]

After sitting that long your points might be glazed.
Use a bit of emery cloth to clean them up.

Here's a link that might help.
http://forums.iboats.com/forum/engi...roubleshoot-a-points-ignition-system?t=335407

 

[LakeTravisAlpha1]

After sitting that long your points might be glazed.
Use a bit of emery cloth to clean them up.

Here's a link that might help.
http://forums.iboats.com/forum/engi...roubleshoot-a-points-ignition-system?t=335407

It has an electronic ignition.

 

[LakeTravisAlpha1]

Ok, after I went out and plunged the lanyard plug in a bunch of times and then hooked up the cord and pushing it in further manually while turning the key, the engine tried to start! It was always a sluggish starter that would barely kick to life like it was starving for fuel and I'd have to hit the throttle at just the right moment to catch it before it died. This time the battery gave out first.
So I'm off to Walmart for a battery trickler. The fuel line where it steps up in size as it goes into the carb has a slight leak as gas seeps around the fitting after I wipe it away so at least I know it's getting gas now.

Speaking of gas leaks, at the sending unit of the gas tank there are three hoses; the big hose to fill the tank, a smaller hose that goes to the fuel pump and another, slightly larger hose that goes to what appears to be a vented bulb protruding out the back of the upper transom. I'm not sure what purpose that one serves other than a vent but it has a slight leak at the tank. I wiped that area down and in a few minutes noticed a wet circle growing larger around the seal where the hose goes in. Whats the best way to re seal that seal? I didn't want to start a new thread just for that issue. Thanks a million.

 

[Alumarine]

It has an electronic ignition.

Oops!

 

[alldodge]

Three hoses to/from the tank
Has a fill hose, vent hose and supply hose. The vent hose is there to allow air to come into the tank and expel back out as pressure changes. Need to fix these leaks and in most cases it's best to replace the fuel line. At least remove the line and see if it is just a bad spot on the hose which can be cut off and reinstalled, or needs replacing

 

[Fun Times]

Ok, after I went out and plunged the lanyard plug in a bunch of times and then hooked up the cord and pushing it in further manually while turning the key, the engine tried to start!

Did the gauges power up while you were operating the lanyard switch?
Do you think you have a defective switch?

It was always a sluggish starter that would barely kick to life like it was starving for fuel and I'd have to hit the throttle at just the right moment to catch it before it died.

Possibly the choke on the carburetor needs adjusting.

This time the battery gave out first.
So I'm off to Walmart for a battery trickler.

I'd be a little concerned that the new battery seems to be dying out so soon. Bear in mind that just because it's new doesn't always mean that it's at it's full capacity when sold new. What size Cold Cranking Amps did you buy? You may want to have it checked to see if it's still within range.
Be sure to repair the fuel leak before heading out on the water.:boom:

 

[LakeTravisAlpha1]

Nope, the gauges never powered up.

It's a new Marine Interstate battery, 625 Cranking Amps, 95 Reserve.

A mechanic buddy that has experience in boats came by this afternoon and we tried to start it. He checked for a spark by pulling a plug and looking for the arc and there was none. There was also no gas going into the carb, which he immediately recognized as a 2 bbl Rochester. (He also knew the 3.0 was made by Gen. Motors and made in Mexico, something I didn't know).

Listening and watching the starter laboring to turn the engine over he said it wasn't turning over fast enough to make a spark, putting the battery under too much a load. He gave me the name of a place in Austin to take it to have it rebuilt, claiming the cost of new ones were stupid expensive. I asked him if I should rebuild the carb too and he said not yet, to eliminate the possible problems one at a time.

Be sure to repair the fuel leak before heading out on the water.:boom:

Actually, it looks like 'leaks' as in two, one where the 3/8th vent hose attaches to the plastic belly tank next to the sending unit and the second one, a slight seepage where the fuel line attaches to the carb at the float. The first one is what has me concerned as I don't want to have to replace the tank, if they even make that model. My Wellcraft Excel is discontinued.