Won't start sometimes, TWO (seperate boats) 1997 Merc OB's

Two of us actually have the exact same issue Both are 1997 Merc's one a 200 and the other a 150.

The 200 does this:

OK, this is pissing me off and there's prolly an obvious thing to do--97 Mercury OB w/carbs starts fine, runs out to fishing place fine, turn off to drift--it even starts again once or multiple times--then, won't start; replaced fuel/water filter; replaced under cowling gas filter; blew air thru fuel vent hose to make sure it is open. New battery (different issue, but still....).

Happened at beginning of last season, but I thought I was out of gas and added/filled and it worked rest of season no probs.

This year--got stuck 2 weeks ago, got a tow. Started as soon as I reached dock.

Today, started, ran fine, started again; drifted for a half hour, wouldn't start. Ball hard, could smell gas even, waited, tried, waited, tried, etc.

Called for a tow; kept trying to start off and on; not sure which try, but, started went home, turned off, started again at dock.

Motor not sputtering, runs normal when it starts.

Any theories? What should I do next? Replace fuel pump? The starter cranks, so I'm guessing it's not electric, but hey? Replace plugs?

......and the 150 did this:

I have the same problem, 1997 Merc 150 offshore. Did it to me last week when at Cole's Point. Ran about a mile to fish. Drifted for about an hour then it wouldn't start. I sat for another hour cranks and won't start even with spray (starting fluid). Sat another hour remove plugs, cleaned and sprayed each. Also opened gas tank in case of vacuum and then tried it and it started. Happened to me once last year too but that is it.

For what it's worth I had new plugs, fresh NON-eth fuel with Startron.

Would love to figure this thing out because I feel uneasy turning it off.


Any and all help you can give us would be greatly appreciated!!!!

Re: Won't start sometimes, TWO (seperate boats) 1997 Merc OB's

No one has any ideas on this?

Re: Won't start sometimes, TWO (seperate boats) 1997 Merc OB's

Which control do you each have?

Seperate fast idle lever or a Neutral button at the Control Lever pivot?

Spell out your entire start sequence.

Level trim before each start, sometimes leveling trim before shutdown will prevent an accumulation of fuel in the airbox which contributes to 'flooded' starting.

Cold start, prime bulb, open throttle half way, or lift fast idle lever little more than half way up, push key IN to choke/enrichen, hold in while cranking, release when engine fires. Be ready to 'bump' choke/enrichener as engine slows and threatens to die. Pull back throttle to maintain rpm @ 2000 until warmed and stable.

Warm start, open throttle half way, or lift fast idle lever.......NO CHOKE, crank until starts. If reluctant to start then push in choke/enrichener and crank, immediately release choke when fire.

Re: Won't start sometimes, TWO (seperate boats) 1997 Merc OB's

CharlieB said:

Which control do you each have?

Seperate fast idle lever or a Neutral button at the Control Lever pivot?

Spell out your entire start sequence.

Level trim before each start, sometimes leveling trim before shutdown will prevent an accumulation of fuel in the airbox which contributes to 'flooded' starting.

Cold start, prime bulb, open throttle half way, or lift fast idle lever little more than half way up, push key IN to choke/enrichen, hold in while cranking, release when engine fires. Be ready to 'bump' choke/enrichener as engine slows and threatens to die. Pull back throttle to maintain rpm @ 2000 until warmed and stable.

Warm start, open throttle half way, or lift fast idle lever.......NO CHOKE, crank until starts. If reluctant to start then push in choke/enrichener and crank, immediately release choke when fire.

Click to expand...

Thanks for replying, the second one is mine. I don't think the trim was anything other then level but could have been because I fish a lot of shallow water and might have had it tilted up a little but not much.

When I start the motor cold I push in the key for a count of five and then turn key. This almost always fires the boat first time but if not I bump the key in and out until it does. When warm I don't push in the key unless it fails to start then I bump it in and out until it does.

Question #1: If it is flooded when it doesn't start would spraying starting fluid in one of the carb air intakes help start it? Probably not since it's already flooded huh? Also this engine has 3 carbs so are they all flooded?

Question #2: When you push in or bump the key what does it actually do? Is it priming the carbs or actually choking it like a carbed car engine?

Thanks for your help it is GREATLY appreciated.

Dave

Re: Won't start sometimes, TWO (seperate boats) 1997 Merc OB's

When they won't start try advancing the throttle A BIT in neutral, if possible.

Re: Won't start sometimes, TWO (seperate boats) 1997 Merc OB's

marc c said:

When they won't start try advancing the throttle A BIT in neutral, if possible.

Click to expand...

I always do that about 1/3 rd forward in neutral on first start of the day and will after if it doesn't start after that. Would you go farther?

Re: Won't start sometimes, TWO (seperate boats) 1997 Merc OB's

First, Never under any circumstances spray starting fluid into an outboard engine. The fuel has the lubrication. Starting fluid has none.

I found with my V6 that it has a preferred starting sequence, and it is different between hot and cold.

Cold, I level the engine (to the lake, boat dependent), pump up the primer, raise the fast idle lever, turn the key on, hold in the enricher without cranking for 5 to 10 seconds (air temperature dependent), crank to start. Nurse it by bumping the enricher for a few seconds as needed, throttle down, watch for tell-tale (shows warm enough to open thermostats), then get underway.

Warm, level engine, start at idle. If it doesn't immediately start, raise the idle lever a little, bump the enricher for a second, and start.

Engine is in good shape, and well tuned. It has one hellova lot of carburetion on it (stock), and thus is a little finicky as any hot rod would be.

If you pay attention to the results when you try different starting sequences, you should be able to come up with a system that always works. The secret is to pay attention, and maybe even take notes.

hope it helps
John

Re: Won't start sometimes, TWO (seperate boats) 1997 Merc OB's

j_martin said:

First, Never under any circumstances spray starting fluid into an outboard engine. The fuel has the lubrication. Starting fluid has none.

I found with my V6 that it has a preferred starting sequence, and it is different between hot and cold.

Cold, I level the engine (to the lake, boat dependent), pump up the primer, raise the fast idle lever, turn the key on, hold in the enricher without cranking for 5 to 10 seconds (air temperature dependent), crank to start. Nurse it by bumping the enricher for a few seconds as needed, throttle down, watch for tell-tale (shows warm enough to open thermostats), then get underway.

Warm, level engine, start at idle. If it doesn't immediately start, raise the idle lever a little, bump the enricher for a second, and start.

Engine is in good shape, and well tuned. It has one hellova lot of carburetion on it (stock), and thus is a little finicky as any hot rod would be.

If you pay attention to the results when you try different starting sequences, you should be able to come up with a system that always works. The secret is to pay attention, and maybe even take notes.

hope it helps
John

Click to expand...

I know starting fluid doesn't have lubricant in it but there is plenty there IMO to protect with all of the fuel in it. BTW I am only firing a short burst to try to help fire it.

So the "choke" is really an enricher? It does what exactly? What about the choke?

As for the rest I do pretty much what you say and 95% of the time have no problems. Once last year and now once this year it won't start for me and I am trying to figure out why. Really shook me up this time because I had a couple children with me etc.

I guess the main thing I am looking for is when this happens what would be the first thing you would check, second, etc.

Thanks and keep the responses coming.

Re: Won't start sometimes, TWO (seperate boats) 1997 Merc OB's

Thoroughbred said:

I know starting fluid doesn't have lubricant in it but there is plenty there IMO to protect with all of the fuel in it. BTW I am only firing a short burst to try to help fire it.

So the "choke" is really an enricher? It does what exactly? What about the choke?

As for the rest I do pretty much what you say and 95% of the time have no problems. Once last year and now once this year it won't start for me and I am trying to figure out why. Really shook me up this time because I had a couple children with me etc.

I guess the main thing I am looking for is when this happens what would be the first thing you would check, second, etc.

Thanks and keep the responses coming.

Click to expand...

The enricher is a valve that connects the bottom of the top float bowl with either 2 or all 3 carbs behind the throttle plate. Stopped, fuel will drip, and cranking it will actually be sucked into the affected cylinders.

One think I would look for... could you be sitting on the kill lanyard, partially operating the kill switch?

Along that line, disconnect the kill wires at the switchboxes, and connect an ohmmeter set on a high range to that wire and ground. It should be open when the key is on, shorted to ground when the key is off. operate the key many times to see if it maybe partially hangs up some times. I'd disconnect the battery and operate the key all the way into the start position. Also, operate the high idle lever, looking for it shorting the wiring. Move the harnesses around while watching the meter. Jiggle the kill switch without operating it, looking for trouble.

hope it helps
John

Re: Won't start sometimes, TWO (seperate boats) 1997 Merc OB's

j_martin said:

The enricher is a valve that connects the bottom of the top float bowl with either 2 or all 3 carbs behind the throttle plate. Stopped, fuel will drip, and cranking it will actually be sucked into the affected cylinders.

One think I would look for... could you be sitting on the kill lanyard, partially operating the kill switch?

Along that line, disconnect the kill wires at the switchboxes, and connect an ohmmeter set on a high range to that wire and ground. It should be open when the key is on, shorted to ground when the key is off. operate the key many times to see if it maybe partially hangs up some times. I'd disconnect the battery and operate the key all the way into the start position. Also, operate the high idle lever, looking for it shorting the wiring. Move the harnesses around while watching the meter. Jiggle the kill switch without operating it, looking for trouble.

hope it helps
John

Click to expand...

I guess it could be the kill switch but I wasn't sitting on the lanyard. It was connected to the ignition key (I know) and of all the things I did before finally getting it started messing with the kill switch wasn't one of them.