Ignition Fuse Keeps Blowing - Help!

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Hope someone can help me out. I have an 2007 18' Stingray with a 3.0L Volvo I/O. The boat has run great for the last 5 years and I only run it in fresh water and store it in my garage. Yesterday it started fine and after running at about 3500 rpm I slowed down to go through a canal. As soon as I slowed it down the 15 amp fuse under the instrument panel for the ignition blew. The next day I bought some new fuses and took the boat out again to trouble shoot. Here are my observations after blowing 4 more fuses:

1. The fuse ONLY blows when I slow down from a high speed to a low speed while moving - it runs fine in all other situations.
2. The fuse does NOT blow when I'm out of gear and I run the engine at a high speed and slow down (it seems like that part of the electrical system wouldn't care if I was in gear or not in gear - right?).
3. I intentionally ran the boat over some wakes to make things bounce around in case there was a loose wire and made a lot of sharp turns, and the fuse never blew.

I'm baffled on why the fuse ONLY blows when slowing down after high speeds. It runs fine when going slow, it runs fine at high speeds, it's only when I slow it down while in gear. It seems like I should be able to reproduce the problem when the boat is out of gear however it does not blow - I tried a dozen times.

Thanks in advance for your help!!!
 

Don S

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Re: Ignition Fuse Keeps Blowing - Help!

Try this and see what happens. (Grab some more fuses) Warm the engine up, then you need to somehow open the choke so it won't close because the automatic choke will not work while testing.

Then disconnect the purple wire from the alternator and go for a run and see if it dies when you back off of it.
 
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Re: Ignition Fuse Keeps Blowing - Help!

Thank you for the reply!!!! I will definitely try that. A couple of additional questions...

1. There are 2 purple wires coming out of the back of the alternator (see picture below) - should I unplug both?
2. Why do I need to open the automatic choke (forgive my ignorance)? It seems to start fine, idle fine, and run fine (except for the fuse blowing when slowing down). Is this necessary? Can I try it without messing with the automatic choke.
3. If I find that unplugging the purple wire from the alternator works, does that mean I need a new alternator?

Thanks again for your help - it is appreciated!



photo.jpg
 

Don S

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Re: Ignition Fuse Keeps Blowing - Help!

Unplug the purple one (to the right of the orange wire), not the purple with white stripe (to the left of the orange wire)
.
The alternator will not charge with the purple wire off. The automatic choke gets power from the alternator when it's working, and it won't be while testing.
 
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Re: Ignition Fuse Keeps Blowing - Help!

Don, thanks for your help and expertise. I just bought some more fuses, however a thunderstorm is about to roll in so I'll have to try it tomorrow. I'll post back once I get a chance to try it out to let you know how it goes.
 
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Re: Ignition Fuse Keeps Blowing - Help!

I was messing around with it in the garage (trying to figure out how to open the choke for when I run it tomorrow). I double checked the ignition fuse next to the engine (different from the one under the display by the key). I pulled it out and then tried to turn the key to see what would happen. It briefly made the "ignition tone" and then it died out (I was surprised it even did it for a split second without the fuse). Anyway, that fuse was fine and so I put it back in place, then tried the key again. This time nothing happened and the fuse under the display was blown. So I put another fuse in and it blew almost right away. This is the first time the fuse blows without even running the engine (before it would only blow when slowing down from high speed). I can't figure out what I could have done to make it worse. I tried another fuse again just for the heck of it and it blew right away as well (I unplugged the purple wire for the alternator to see if it made a difference). So now I guess I can't try it on the lake. At this point I have no idea what the problem is. Any thoughts?
 

Don S

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Re: Ignition Fuse Keeps Blowing - Help!

What is the full model number or serial number of your engine?

It looks like you have a fuse/relay box on the back of your engine. I would be looking hard at the wiring for chaffed wires that could be shorting. Even if you have to take that box of the motor to see the underside where the wiring is, you have to look.
 
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Re: Ignition Fuse Keeps Blowing - Help!

Hi Don, thanks again for your help - it is definitely appreciated.

It's a Volvo Penta 3.0GLP-E engine

Here are a couple of pictures. The 2nd one is of the fuse panel by the engine (this one has NOT had any blown fuses, only the one under the display panel). I looked for any damaged wires, however I do not see any. You may notice in the first picture a disconnected cable on the left side on the floor, that's for the bilge - this model boat has a bilge that runs briefly every 2 1/2 minutes day and night and slowly drains the battery, so I've had it disconnected since I bought it 5 years ago.

Also, I pulled off the display panel to check the ignition key wires and they look good too. The boat stays in the garage, so everything is in great shape from a corrosion/weathering standpoint.

photo2.jpgphoto.jpg
 

Don S

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Re: Ignition Fuse Keeps Blowing - Help!

In the picture on the right, you have 2 small relays above the 40A Yellow fuse. Swap them.
The one on the right is the ignition relay, the one on the left is a spare and goes to nothing.
 
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Re: Ignition Fuse Keeps Blowing - Help!

Okay - I just did and it started right up, no problems (it's in my garage so I only ran it for 3 or 4 seconds). So that is great news! So then I switched them back to see if it would blow the fuse again, and it did not - it also started right up. So both relays let me start this time - why it was blowing a fuse a few of hours ago is a mystery. It makes me think your earlier hypothesis of a chaffed wire, may be the culprit. That being said, everything looks in perfect condition.

I should also mention that the time between the fuses blowing a few hours ago and now when I swapped relays, I removed the instrument panel to look at the wires behind the ignition key switch. Everything looked fine, however maybe I re-adjusted a wire/connection so that it worked again.

Also, I read on another post for a 5 liter Volvo, a guy said there is a special wire that brings 12V directly to the ignition switch from the starter solenoid, which is to bring more juice to the ignition switch when starting. He said he found that the Vovlo Penta starter solenoids were poorly designed - could this be a possible source of the problem? The name of the thread is: "Volvo Penta Ignition Fuse Blowing" on a website called www.thehulltruth.com

Thanks!
 

Don S

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Re: Ignition Fuse Keeps Blowing - Help!

It may still be a faulty relay, have no clue about the post from THT, post a link to the thread, not just forum, I'm not going looking for it.
But, the relays are Bosch, not Volvo, so it's nothing to do with the relays being of poor quality, and I have no clue what 5.0L engine it is, or if it has the same wiring as yours or anything else.
I would sure run it (on the water) with the spare relay installed and see what happens.
 
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Re: Ignition Fuse Keeps Blowing - Help!

Hi Don,

I finally was able to get the boat on the water... It started fine, however after putting it in gear the fuse blew after 2 - 3 seconds. So I swapped relays and it started up and I ran it perfectly for a solid 15 - 20 minutes at all different speeds, over wakes, reverse, hard turns, etc and the fuse did not blow. However, I swapped the relays back to see if in fact that was the problem and it ran perfectly that way too - no problems at all. I was not able to blow the fuse again. So I have no idea what the problem is. My only guess is a loose wire, however it seems like I could have gotten the fuse blow at least once, especially after blowing 8 or 9 fuses so easily on the last outing and in the garage. I cringe at the idea of taking it into the boat mechanic if I can't get the problem to occur so he can trouble shoot it.

Could it still be the relay? I didn't try the alternator check because it was working perfectly and I couldn't reproduce the problem. So there really isn't any peace of mind for the next time I take people out on it. I can bring a bunch of fuses, which would be fine, however there was the one time in the garage where the fuse would blow immediately when turning the ignition key. Any other thoughts?

Thanks!!!
 

Don S

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Re: Ignition Fuse Keeps Blowing - Help!

Sure it could be the relay. Something loose inside, who knows. Keep the new one in and run it for a while and see what happens.

I would check under the relay box and look at the wiring if it's open. If an enclosed box, try the new relay and see if it cures the problem over time.
 
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Re: Ignition Fuse Keeps Blowing - Help!

Don, thanks for the information. I will definitely keep the new relay in and see if it ever happens again. I'll report back after a few boat outings in case someone else has a similar problem.

Thanks again for all of your help, it is really appreciated!!!!
 

seanreymond

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Re: Ignition Fuse Keeps Blowing - Help!

Don, thanks for the information. I will definitely keep the new relay in and see if it ever happens again. I'll report back after a few boat outings in case someone else has a similar problem.

Thanks again for all of your help, it is really appreciated!!!!

Big sand lake,
Did the new relay solve your problem? I am having the exact same issue with my boat.
Thanks!
 
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Re: Ignition Fuse Keeps Blowing - Help!

Hi Seanreymond,

My boat has been working fine since my last thread. I wish I could tell you what the problem was. I swapped the relay back in April as recommended by Don S above and it worked great, however I switched back to the old one to try to reproduce the failure to verifty problem and it has worked fine ever sense (so I have left the original relay in ever sense). I just had the boat out yesterday. I'm glad it works, however it's a little frustrating because everytime I take it out I wonder if the problem will return. I wish I had a better answer.
 
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Re: Ignition Fuse Keeps Blowing - Help!

Big sand lake,
Did the new relay solve your problem? I am having the exact same issue with my boat.
Thanks!

Hey Seanreymond,

Did you ever figure out your electrical problem? It's been 2 years since mine, and it just happened again yesterday and today for the first time since. Very frustrating. This time I put in the extra relay and it still blew the ignition fuse.
 
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Re: Ignition Fuse Keeps Blowing - Help!

I'm hoping somebody reads this that may have an idea of the best course of action. As you can see in the thread I had this electrical problem about 2 years ago, and after troubleshooting for a few days it fixed itself for lack of a better term. I tried Don S' advice and swapped relays and the boat worked great, the only issue is I put the old one back in to see if I could get it to fail again and it has worked fine ever since (until yesterday). This makes me wonder if it was ever really the relay. So yesterday I was running it at probably 3500 RPMs and all of a sudden everything died. Sure enough the 15A ignition fuse under the instrument panel was blown (just like 2 years ago). I swapped relays in the engine compartment and put in a new fuse and it ran fine. This morning I ran it and it blew the fuse again! It happened when I pulled back on the throttle from about 3500 RPMs (which was the same failure mode 2 years ago) - this was the first time it ever happened with the other relay. It's a very intermittent electrical problem, so I'm nervous about taking it to a mechanic if they can't reproduce it. Has anyone ever experienced this problem? I'm curious if you found the root cause. The beginning of this thread has more details and some pictures too. Thanks in advance for anyone's feedback!!!!
 

bruceb58

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Re: Ignition Fuse Keeps Blowing - Help!

Could be the wire that supplies voltage to the trim switch is rubbing against something.
 

seanreymond

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Re: Ignition Fuse Keeps Blowing - Help!

Hey Seanreymond,

Did you ever figure out your electrical problem? It's been 2 years since mine, and it just happened again yesterday and today for the first time since. Very frustrating. This time I put in the extra relay and it still blew the ignition fuse.



I had has chafed (bare) wire that hit the engine block when I went from cruising speed to idle. I put some electrical tape on it and it has been fine for 2 years.
 
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