2009 Stingray 205lx with Volvo Penta 5.0 GXi hissing noise, shudders, and dies

[sms1976]

I have a pretty new-to-me boat with a Volvo Penta 5.0 GXi, with around 260 hours. I've put probably 15 hours on it this summer with no trouble.

Today after being out for about an hour, we were pulling a tube at about 15 mph when the motor slowed to a very rough idle and started making a loud hissing or wheezing noise. I shut it down, and waited a bit to re-start. When I restarted, it wouldn't run faster than an idle, it made the loud hissing noise, and it died on its own. I got a tow back to shore and have hauled it home, where I can run it on a hose if needed.

Anyone know where to start on this? I can't find any similar stories on this forum, but it could just be I'm not searching effectively. Thanks in advance for your advice!

 

[rtoomey641]

I have a 5.7 that was doing weird stuff turned out to be the 10 pin connection they are prone for shorting I had my mechanic hard wire it’s fine now mine is fuel injected and I noticed when I bumped connecter by accident fuel pump would cut out and restart might not be your problem but worth a peak

 

[89retta]

Can you post a video of it running if you can get it to start on the hose

 

[sms1976]

I'll get a video tomorrow if I can get it started, as well as taking a look at the connections. I should add that I was at not much more than an idle for quite awhile (~30 minutes) when the issue arose.

 

[Lou C]

A hissing noise can be from a vacuum leak from a bad gasket or other fitting that has a vacuum hose attached to it.

 

[stouchton]

Loud hiss combined with fast idle is usually the IAC motor opening up trying to get her to run because you might have a fuel delivery problem - check your fuel pump (or fuel tank/lines for that matter).

 

[sms1976]

Can you post a video of it running if you can get it to start on the hose

Here is the (short) video of the hissing noise.

 

[sms1976]

After taking off the cover, and taking that video, it wouldn't start again. So I pulled off the spark arrestor and the noise is definitely coming from the small opening behind the throttle body, I am assuming the Idle Air Control Valve.

 

[sms1976]

I don't have any fuel system diagostics tools (like a pressure gauge) but I might get the boat filled up with gas and see if I can change the fuel filter to start. Maybe AutoZone or O'Reilly's has a loaner tool that would work. Is it the same as one for normal cars? And is there a service manual for this to work through the diagnostics? I had a service manual for the 3.0GL that I had previously. Thanks again!

 

[89retta]

This is for 5.0 GXI . Look at part #18 is it possible that cap came off and is allowing more air into the throttle body. www.marinepartseurope.com/en/volvo-penta-explodedview-7744300-25-7506.aspx

 

[sms1976]

This is for 5.0 GXI . Look at part #18 is it possible that cap came off and is allowing more air into the throttle body. www.marinepartseurope.com/en/volvo-penta-explodedview-7744300-25-7506.aspx

I don’t see a cap like that on this one, the 5.0GXi-J:

 

[sms1976]

As an update, I pulled off the fuel pressure regulator, and it popped out under pretty high pressure. Not sure if that's normal, but it also had a few tiny bits of black on the screen. Is that the screen that Volvo Penta has recommended removing? And if so, what do I replace that with?

 

[sms1976]

Well the problem is fixed with some new gas. I found some ethanol-free premium and filled it up (22 gallons in a 35 gallon tank, gauge was showing 1/4 tank or so). It still wouldn't start with several tries, but with a few sprays of starter fluid (also checking to see if there was a different vacuum issue) it sputtered to life and after a few minutes ran pretty smoothly.

I got it up to operating temperature and the hissing is still there at idle, but not as bad. I hadn't noticed the hissing before, so I might just be more tuned in to that. We'll see how it goes on the lake this weekend. I hope it was just some bad gas or water in the tank that caused that. Thanks for your help everybody!