what should the volvo do on muffs?

[jlgab345]

We are trying to trouble shoot the engine issue with an audible alarm going off. When running our volvo 5.7l gi on muffs no water comes out of the prop, is that normal?

Assuming water was supposed to come out of the exhaust, the engine may not be getting enough water through it to cool it?

What should I be checking?

Thanks!

 

[Don S]

Re: what should the volvo do on muffs?

Volvo has been using the 5.7 since the 70's, think you might help us narrow it down a little. Like a full model or serial number.

Does water come out the back of the boat anywhere? Not all Volvos have exhaust through the prop.

 

[jlgab345]

Re: what should the volvo do on muffs?

Sorry! Engine is 2002 volvo penta 5.7l gl with an sx outdrive.

product #3868890 and serial #4202036706

We think we narrowed it to the exhaust sensor. Switched the oil pressure sensor and exhaust sensor and the exhaust side still went off. Might the impeller be blown?

Thanks in advance. Not quite sure what info to give as we are newbies.

 

[zbnutcase]

Re: what should the volvo do on muffs?

Those pumps are designed PUSH water, not PULL it (thats why they are down low by the waterline) and a lot of times they simply wont function on muffs. I connect the hose directly to the pump inlet.

 

[Don S]

Re: what should the volvo do on muffs?

I've been running those drives on muffs for years with no problem, you do have to have a good impeller to pull the water up from the drive. The impeller should be replaced every other year. In any overheat problems on a boat, the first thing to check is the impeller. They can be damaged by so many things.

You have a 5.7GL-A (2001) engine.

We think we narrowed it to the exhaust sensor. Switched the oil pressure sensor and exhaust sensor and the exhaust side still went off. Might the impeller be blown?

Not sure how you pulled that off, or why, if you want to find out which sensor is causing the alarm to go off, disconnect each sensor till you find the one that stops the alarm.

 

[jlgab345]

Re: what should the volvo do on muffs?

Sorry I misunderstood what hubby told me he did...I had it wrong.

He's opening the water pump now to replace the impeller. We ran it for a few sessions of a few min to 10 min this morning to figure out the sensor that was going off. If it was the impellor, would that have caused serious damage to engine?

 

[Don S]

Re: what should the volvo do on muffs?

It all depends on how hot it got, and how long it was hot. If the engine was shut down when the alarm goes off, there shouldn't be any damage to the engine. The alarm sounds at 210? which is hot for a marine engine because of the enclosed area that it lives, but 210? is about normal temp for a car. Serious damage won't happen till after 260? or so. The worst that would happen is the exhaust hoses would burn up due to lack of cooling water on them.