Logo

Need Help, Volvo Penta 4.3GL Issues...

Dioc_V

New member
I'm helping a friend fix his ski boat and having some odd issues.

It ran fine last season, but sadly, the owner did not put any fuel stabilizer in the tank and didn't even bother to fill it. The first problem was it would not start. Then, with the help of someone on the iboat forum, we created a jumper and got the fuel pump to work by connecting and disconnecting the power. It started clicking until it broke loose and began pumping again. Assuming it was from the bad gas turning to varnish due to the owner not putting any stabilizer in and gumming up the pump.

We were able to finally get the pump to break loos and work, and the motor to finally start, but it sounded like the starter was not disengaging.

There were problems with the ignition switch on the dash and it felt like the starter circuit was not releasing. We replaced the ignition switch but still, the motor would start, but not continue running once you released the key to the "run" position.

We were instructed by someone on another site to test the line from the alternator to the fuel pump relay using a volt meter and we got 1.65 to 1.67 at the alternator and .02 at the relay plug.

Now they're saying it's a bad alternator but they problems don't seem to be related.

They seem like unrelated issues, i.e.:
- Gummed fuel-pump
- Starter wont disengage
- Motor starts but won't run.
- And now bad alternator?

What could explain all this? Is this a correct diagnosis? Can a bad alternator cause all these problems?

Thanks much!

Doc_V
 
Last edited:
Doc, I see nothing wrong with paying for diagnostics up front, as long as the diagnostics truly identify the problem, and when the problem area/item is corrected/replaced, that it cures the problem.
Get this in written form!

There is no sense in paying for parts that, A) were not itemized in the diagnostics, and B) did not correct the problem.

Granted...... some items are difficult to diagnose right off the bat.

.
 
It's not my boat, it's my friend's, but he's not very handy with tools and knows little about working on motors. He checked with his local shop, but they have a 2 month waiting list, so we're trying to see what we can do in the mean time. What I listed above is what we found following the advice of someone on another board, but they haven't been very forthcoming with details as to what could have caused the problems. So I'm looking for both a second opinion as well as some insight as to the cause. I don't like doing things without knowing why I'm doing them, especially when it's not my boat. So tabling the "taking it to a shop" idea for now, I'd appreciate any and all info that might help me proceed.

Thanks.

Doc_V
 
Doc, I think that we need more information from you.

Which 4.3GL?

Look here and find your 4.3 GL model number.... there are many.
http://www.marinepartseurope.com/en/volvo-penta-schematics-MarineGasolineEngines.aspx
Is this carbureted? I believe that some are TBI.

Either will use an Electric fuel pump with electrical power that is routed through a low oil pressure shut down switch. (USCG regulations).
A start by-pass circuit brings the pump in during cranking.
If this circuit fails, you'll loose fuel pressure once out of starter motor by-pass mode.

If the system is using alternator output for continuing fuel pump operation, that may explain the alternator involvement.
See your Volvo Penta OEM service manual trouble shooting section. Not Seloc or Clymers.

What climate was this old fuel stored in? Hot summer climate, or cooler climate?
This makes a difference in how well fuel survives being stored.
 
The motor is a 4.3GLPBYC

The boat is located in the San Francisco bay area, were temps are pretty moderate during the off season when it sat. Lows from 30s to highs of 60's

We concluded the pump wasn't working, but weren't sure the cause. Realizing, among other things, it could be the relay, and based on a suggestion from the other site, we tested they relay by jumping two terminals on the plug. Doing so, we were able to supply constant power to the pump, regardless of key position.

At first, all we heard was a click. Thinking it might be frozen due to the gas turning to varnish, I tried disconnecting and reconnecting the power repeatedly, until the pump finally broke loose and began running again.

At that point, *the motor did start and was running*, but it sounded as if the starter was not disengaging. So we turned the motor off, then tried again, hoping the starter would disengage. Each time it ran, but still made the noise.

After a few minutes of trying to start and stop the engine, to get the starter to disengage, the motor would start, but now it would not continue to run once the ignition key was released from the "start" position.

It just so happens, that the owner was also having problems with the ignition key sticking, so we thought that might be the cause.

At the time, considering the issues with the key sticking, it made sense that was the problem, so we replaced the ignition switch. But the problem continued.

So, the next thing that came to mind was the carb. It made sense that after a few minutes of running, whatever varnish was gumming up the fuel pump, could have broken loose and clogged the main jet on the carb.

This is the first boat motor I've worked on, and I don't know anything about this particular carb, so I'm just hypothesizing here. If I understand correctly, when the key is turned, a starter [or enricher] jet is supplying fuel, allowing the motor to start. But the second you release the key from the start position, the "starter" jet stops squirting fuel… and the main jet keeps the motor running. But if the main jet is clogged, the motor can't continue running. Correct?

It's what makes sense to me, but being that it's not my boat and not knowing a lot about it, I'm not really in a hurry to begin dismantling the carb.

So I posted my results on the other site, but didn't mention my theory about the carb, just what happened, and they suggested I test the alternator as mentioned in my original post. Based on the results of that test, they're suggesting the alternator be repaired or replaced, but with no other details.

Being that it's not my boat, and I don't want to cost my friend lots of money by replacing random parts, I'm reluctant to proceed with the alternator. Besides, I'm still not convinced it's not the carb.

So here I am looking for a second opinion and could use any and all insight you can provide.

Thanks.

Doc_V
 
Last edited:
You need to look at this schematically.

During starting only, the S terminal of the starter motor solenoid is used to power the fuel pump relay.
Once up and running, this drops out of the loop, and oil pressure closes the main fuel pump circuit!

Apparently the way in which you are circumventing the low oil pressure switch and/or relay, is keeping the S terminal of the starter motor solenoid energized.
This is very likely why you are seeing continuned operation of the starter motor.

Try temporarily taking this out of the loop when you engergize the fuel pump.

Remember, the low oil pressure switch must be able to cut power to the fuel pump during low pressure (i.e., non-running engine)
This is a USCG rule....
so DO NOT leave this wired in a fashion whereby low oil pressure will NOT kill the pump circuit.


.
 
I'm helping a friend fix his ski boat and having some odd issues.

It ran fine last season, but sadly, the owner did not put any fuel stabilizer in the tank and didn't even bother to fill it. The first problem was it would not start. Then, with the help of someone on the iboat forum, we created a jumper and got the fuel pump to work by connecting and disconnecting the power. It started clicking until it broke loose and began pumping again. Assuming it was from the bad gas turning to varnish due to the owner not putting any stabilizer in and gumming up the pump.

We were able to finally get the pump to break loos and work, and the motor to finally start, but it sounded like the starter was not disengaging.

There were problems with the ignition switch on the dash and it felt like the starter circuit was not releasing. We replaced the ignition switch but still, the motor would start, but not continue running once you released the key to the "run" position.

We were instructed by someone on another site to test the line from the alternator to the fuel pump relay using a volt meter and we got 1.65 to 1.67 at the alternator and .02 at the relay plug.

Now they're saying it's a bad alternator but they problems don't seem to be related.

They seem like unrelated issues, i.e.:
- Gummed fuel-pump
- Starter wont disengage
- Motor starts but won't run.
- And now bad alternator?

What could explain all this? Is this a correct diagnosis? Can a bad alternator cause all these problems?

Thanks much!

Doc_V

There is a relay that goes from the alternator to the fuel pump on the 4.3 Volvo Penta. If it is bad the boat will start and run for 30-45 seconds then quit. It happened to me when my dumb ass mechanic installed the wrong alternator on my boat this summer.
 
Back
Top