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Rare starting problem, please help 1993 4.3 L

Y

yannicksjh

New member
Hi, i have a 1993 Stingray 609zpx with a 4.3LX merc. Bought the boat last season and came accross these two problems that rarely occur. I'm having a hard time fiding what'swrong with it even from machenics since it rarely happens.

1. Problem 1 has happened twice last year and once this year so far. I used the boat on the previois day and then the very next day I go to start the boat and it doesn't. Its getting fuel and sparks just won't catch. Turns over like its starting when holding the key ON but just never starts. Its not flooded, battery(s) are fully charged. I tried for over an hour checking different stuff and nothing. then 1 last try before i leave and it starts??? turn it ON and OFF 10 times after that and it starts fine. Like i said this problem has only happened a few time when starting from cold and has never happenned on the water YET!. I know its hard to diagnose with out seeing but figured i'd ask.

2. This too rarely happens and not sure if its related to problem 1 but when moving at a regular speed anywhere from 15-35MPH the engine or something seems to stop for a second or two that catch back ON. Wife always says to quit doing that (or quit hitting the brakes, LOL). It never completly stalls out just enopugh to loose alot of speed and throw you forward a bit. I though it was maybe the prop hub slipping but its done it to two seperate props now. I don't know if the engine is loosing power for that second or what.

Just a note that there is newer spark plugs in and the problem was there before and after installing them.

Could it be the ignition coil going bad? Ignition sensor? interupter switch?
thanks in advance!
 
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Re: Rare starting problem, please help

You don't state the year. Pull the main engine barrel plug and check it for a loose pin or some corrosion. Do the same for other plugs, cables and connectors on the engine. I had a cracked battery cable head once and it drove crazy.
 
Re: Rare starting problem, please help

Hi, sorry, i just edited the post. its a 1993. thanks for the suggestion, i'll double check all the ignition wires.
 
Re: Rare starting problem, please help

how about the kill switch, the key switch. The main ground on the motor, the battery lugs clean. The cables good. The starter connections. the slav connections.

Next time it happens run a jumper from the pos lug to the coil straight. Try to start it.

Pay close attention to the key switch and the kill switch maybe corroded on the back.
 
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Re: Rare starting problem, please help

Oh Guy read today someone else had the same problem, easy to over look and the most basic of trouble shoot for this kind of problem. Ground also people overlook it.
 
Re: Rare starting problem, please help

I just don't get it because it only happens once every 20 times i use the boat and its never happenned to me out on the water YET. Every other time the boat starts great. I guess these type of problems are harder to find then if it never started. Oh sorry, what is the slav connection? Both my batteries are good, batteries cables are like new with new connections. key switch has been replaced but i'll check the kill swith for corrosion or to see if it might be loose.

Also what do you mean by this " run a jumper from the pos lug to the coil straight. Try to start it." Do you mean from the + battery terminal right to the + on the ignition coil". Then i'll know if its between the key swith wiring to the coil OR from the coil forward?

Thanks you so much for your help!
 
Re: Rare starting problem, please help

Where does the pos battery cable go to first ? Thats a slav or relay. With a jumper it will tell you it's maybe the wiring between the pos lug and the coil.

Could be the barrel plug. could be the ground, you say the key switch is good.

Could be as simple as a wire end about to go.

When you start cleaning connections disconnect the battery.
 
Re: Rare starting problem, please help

"batteries cables are like new with new connections."

Do you mean the teminal ends werre replaced? As chiefalen says it just may be a wire end about to go. Tug and pull on the wires while it is running at idle. Pay particular attention to wires that are stretched w/out slack in them and wires that wiggle from engine idle.
 
Re: Rare starting problem, please help

Well, took out the boat last Sunday. Started perfect , Idles perfect then 10-15 min into were i was going it hesitated a few times then died, FOR GOOD! (first time that i had to get towed in). I can usually start it back up but it seems from all the other times i had a hard time starting it the starter finaly went (i hope). Just pulled the starter out and having it checked/ rebuilt tommorrow. Once that problem is fixed, i'll be able to continue finding out why its cutting out in the first place. thanks
 
Re: Rare starting problem, please help

Well sorry to double post but now that i think about it, the boat never hesitates when i'm going slow, only on rougher water going 15-35 MPH which could explain the shift interupter switch slipping OPEN causing the motor to die down OR when using the boat the next day after having no issues the day before, the boat won't start because the switch stays stuck closed after putting it in neutral the day before (so the engine thinks its in gear and won't start). please tell me if that makesd sense? thanks again
 
Re: Rare starting problem, please help

Yes it does make sense. Next time it occurs check the switch. It may be sticking internally. The spring in it may be week and vibrations cause it to activate when it shouldn't.
 
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