mercruiser 4.3l mpi pressure regulator hose to tee

[Chris M Wilson]

We have a 2002 Mercruiser 4.3 L MPI engine with a group of small hoses connected to a Tee at the top of the engine. We can see them connected at the top but the longest line routes to the stern and seems to be dangling free down in the bilge area, not connected to anything.

This does not make sense and we are hoping someone knows if dangling free is the intent and proper? or where it is supposed to be connected?

The system in question is shown in the attached diagram - red highlighted balloons (21) indicating the hoses in question.

Our main question is about one of them that go to the stern and down toward the bilge and to what it should be connected.

If someone knows where it should be connected, can the location and/or component to which it connects be described? We have been unsuccessful in locating anything obvious so far.

Hoping someone can help.

Thanks

 

[Bondo]

Ayuh,.... It's a vacuum line, maybe to the cool fuel, or fuel pressure regulator,.....

 

[Fun Times]

Ayuh,.... It's a vacuum line, maybe to the cool fuel, or fuel pressure regulator,.....

Yes, this one sure sounds like it would be to the F.P.R... See item numbers 19 and 27, https://www.mercruiserparts.com/bam/subassembly/31499/7801/50

 

[Chris M Wilson]

Thanks for the feedback. We changed the pump and the regulator on the cooler system before the past boating season here in Michigan. The boat fuel pump was acting up and the new one (with the new regulator) worked well. I read in another post that the regulator may allow a higher pressure in the fuel rail if it is disconnected. So, theoretically, the boat would still operate so it is possible that the line in question being disconnected may not have had obvious consequences.

It is unlikely we did not connect all the vacuum lines in changing the pump and regulator but, without confessing to other dumb things we have done, it is not beyond the realm of possibility.

We will check it out within the next week and I will provide an update with what we found or have more details about the situation.

 

[Chris M Wilson]

OK. We checked the regulator on the fuel cooler and, lo and behold, there was no vacuum hose connected to the regulator.

We are not sure how it was we left that off given how visually obvious it is when the hose is missing. We think there is a good chance that during other steps in completing the installation of the new pump, fuel line and water line connections we may have inadvertantly pulled the hose off the regulator male fitting tube, for lack of a better term. You probably know how awkward it is to change that pump.

So, bottom line, you guys were right and we thank you for your time and advice.

What is surprising is the thing seemed to run just fine without the line connected. It will be a few months before the lake ice goes away and we can drop it in to see if there is a difference (hopefully positive).

If I can remember, I'll try to give an update at that time.

Thanks again.

 

[Prop head]

We have a 2002 Mercruiser 4.3 L MPI engine with a group of small hoses connected to a Tee at the top of the engine. We can see them connected at the top but the longest line routes to the stern and seems to be dangling free down in the bilge area, not connected to anything.

This does not make sense and we are hoping someone knows if dangling free is the intent and proper? or where it is supposed to be connected?

The system in question is shown in the attached diagram - red highlighted balloons (21) indicating the hoses in question.

Our main question is about one of them that go to the stern and down toward the bilge and to what it should be connected.

If someone knows where it should be connected, can the location and/or component to which it connects be described? We have been unsuccessful in locating anything obvious so far.

Hoping someone can help.

Thanks

Boy seems like these guys have no idea what they are doing! I would be embarrassed to post a question like this. LOL!! Hi Dad!!!!

 

[aspeck]

Boy seems like these guys have no idea what they are doing! I would be embarrassed to post a question like this. LOL!! Hi Dad!!!!

That's what we like ... father and son working together on a boat and having fun at each others expense! You guys are doing it right ... well, sort of ... at least the father and son gig! LOL!

 

[Chris M Wilson]

OK. We checked the regulator on the fuel cooler and, lo and behold, there was no vacuum hose connected to the regulator.

We are not sure how it was we left that off given how visually obvious it is when the hose is missing. We think there is a good chance that during other steps in completing the installation of the new pump, fuel line and water line connections we may have inadvertantly pulled the hose off the regulator male fitting tube, for lack of a better term. You probably know how awkward it is to change that pump.

So, bottom line, you guys were right and we thank you for your time and advice.

What is surprising is the thing seemed to run just fine without the line connected. It will be a few months before the lake ice goes away and we can drop it in to see if there is a difference (hopefully positive).

If I can remember, I'll try to give an update at that time.

Thanks again.

Well the update is the boat ran perfect, better than before. We did a lot of other work on it but we are convinced getting the vacuum hose attached back where it belonged helped a lot at low idle. Thanks.