97 volvo penta 4.3 gl multiple problems

[97larson]

I changed the power valve out (actually used the one I took out of carb originally) fired it up and all is fine. Still not sure exactly what size the power valve is since the markings on the original are no longer there. Of the 2 power valves I received in the kit the 2.5 was visually the closest match, but obviously was too small. The 4.5 supplied in the kit may have been OK, but i put in what I knew should work, Keep the 4.5 for a backup if needed.Thanks to AllDodge, Lou c and everybody else for your suggestions and tips.

 

[97larson]

well....I'm back again and the problems not fixed. Took the boat out and it planed, ran at high rpm and I thought all was OK.Then occasionally it would cut out. then pick up run fine and them cut out. Finally it just gave out and wouldn't start. Same thing, it will fire, and die. So this time I ran all the general tests for the power supply to the fuel pump and all checked OK. Then I tore into the wiring harness and found the diode on the green wire from alternator. Diode tested bad, allowing current in both directions.
2 questions:
Can a diode intermittently work? It seems to me if its bad its bad and it shouldn't run at all. That is the case now, but I wonder about the on off on off condition the pump displayed before the boat was DOA.
Where can I find the correct diode? I can't find a listing for it on any site. The diode has the markings MS on top and IN5399 below.
No radio shack any more, so that option is out.
Does anybody have a part # for the diode.
engine model is 4.3gl-plkd

 

[alldodge]

Radio shack is online, as well as other places

If you search 1N5399 it shows up for less then $1, and is a 1 amp diode
I would search for a 3 amp diode and use it, like 1N5402

Yes a diode can make/break connection as it heats up

Now the diode coming from the ALT will not keep the engine from starting but can stop the fuel pump and the motor will die when it runs out of gas. So long as the relay gets power while cranking this will be enough to fill the carb

 

[97larson]

I ordered the IN5402, now just wait for it to arrive. Could only get a pack of 50, so I will have plenty if it happens again.

 

[97larson]

I put a new diode in (banded positive end) toward the relay plug. Still nothing. Fuel filter is full of fuel and plenty of fuel squirting into carb when I pump accelerator. it will start briefly and die. I'm beginning to suspect the alternator is bad. I connected the volt meter to the green wire post on alternator and pumped the accelerator to keep it running as long as possible. the voltmeter reading jumped around while cranking, as soon as the engine fired it read OF. I did the same thing watching the volt gauge on the dash. Once it fired and ran for a few seconds the voltmeter never went above 12. Just reading battery voltage.I took the alternator off and took it to O'reilly to see if they could test it, they said the information they have says it has to be tested on the motor with a portable tester. Well that won't work if the damm thing won't run.
So, what to do?
Try to find an auto electric shop, but the only one I know of in town that possibly could have done it closed their doors.
I really don't want to throw an alternator on not knowing if this one is bad. I suspect it is, but can't verify for sure.
Any thoughts?

 

[alldodge]

With the motor only starting and not running I don't see it being the fuel pump. Once a carb is full of fuel it should run for a few minutes just idling. Since it starts and immediately dies, this sounds like an electrical problem. The ALT is not the current issue unless its shorted.

Disconnect the all wires from the ALT but leave it in place. The ALT has a purple and a green wire at one connection, jump those 2 wires together. What this will do is power the fuel pump as soon as the key is turned ON.

Try to start and see if it will run

 

[97larson]

i already had the alternator off. Took it to a reputable auto electric shop 30 minutes away. They had no problem testing it and they said it was dead. I left for them to repair/rebuild and will install it next week and see what happens. The problem with the alternator must have blown out the diode as well. Hopefully all the symptoms are attributed to the alternator and all will be well. This has been frustrating as hell.

 

[Wellcraftexcel]

Hi 97L,
Curious what Fuel pump you purchased for ur 4.3 gl ..’97? Where’d you get it from? Was install as easy as it seems?
good luck with your ongoing issues. What a PIA for sure. Frustrating.

 

[97larson]

I bought the fuel pump on e-bay. It is an original equipment pump, all markings matched the original pump including part #’s. Think I paid around $95 for it. Ebay has a lot of cheaper imitations listed, think I would stay away form those

 

[Wellcraftexcel]

Interesting since VP want about $400 for the pump! You might have a counterfeit?

 

[97larson]

Guess that is always a possibility, but if it is they did a very good job with the counterfeiting process.
This is a link to a pump like the one I bought from the same dealer.

 

[97larson]

Got the alternator back, put it in and same problem,
So then jumped the fuel pump at the relay plug, and tried to start engine. Still no go. The carb is getting fuel and the pump is working.
I did not disconnect the wires from alternator and jump green/purple wire to see if pump came on with ignition key. There is more than enough fuel it the bowl to run for at least a minute at idle.
I really don't think this is fuel problem. The engine fires while cranking, but I suspect as soon as i release key it is losing spark. Had a spare ignition I installed--no difference.
Then I connected remote starter switch, started motor and worked throttle by hand. Engine would run and rev as long as I kept the switch engaged, as soon as I let off switch it would die. I discovered this by mistake, but what the hell?
So far replaced relay, diode, fuel pump, repaired alternator and still have the same problem.
checked spark-strong spark while cranking.
Is there a connection/component that would prohibit spark once cranking is stopped?

 

[alldodge]

Is there a connection/component that would prohibit spark once cranking is stopped?

The key switch.

The key should have power on the purple wire when key is turned to ON and keep power on the wire when cranking.

 

[97larson]

Hello Dodge,

I changed out the key switch to another one I had and the same problem exists. I will check for power at the purple wire and during cranking. I know power is flowing during cranking, because i have strong spark and the engine will fire, its once I let off key switch or remote switch that everything dies. The wiring diagram indicates the purple wire routes from switch to starter with a splice in between to coil.The wiring diagram does not indicate the lanyard switch. I have not looked, but does the purple ignition wire run through the lanyard switch? If so, could there be a problem there? I changed the solenoid on the starter to rule out any problem with it (had another good one from old starter) and that made no change. It makes since it would not since the splice to the coil is before the starter. As far as the motor running as long as the switch is to start or jumped with remote switch it makes no sense since i am jumping the yellow/red wire to the starter battery post.If I jumped the purple wire to battery I could see where that could bypass any solenoid/switch problem and supply constant voltage to the coil, but that was not the case.I see no other components in the wiring diagram that would interfere with a constant voltage from the starter switch to the coil.I/m considering removing the purple wire from starter and jumping to 12 volt to see if it will run that way. I feel like i'm chasing a ghost.

 

[alldodge]

Have been unable to find how a lanyard (kill) switch would be wired kenny nunez or Bt Doctur have any ideas?

 

[alldodge]

That said, the same should happen as with a Merc, if the kill switch is on the purple, it would kill the motor when flipped

 

[97larson]

The kill switch is on the purple, I bypassed the kill switch and it started and ran perfect. Hopefully I have found my ghost. What a pain in the ass.

 

[97larson]

Issue resolved. Took boat out on the water and it performed flawlessly with the lanyard kill switch bypassed. Ordered a new switch. Now I can move on to other projects. Thanks to everyone who posted to help solve the problem.