Changing Racor & On engine fuel filter?

[OldDan1943]

Or, run your fuel polishing system more often.
Dont forget the change the o'rings on the fuel deck fill caps.

 

[catalinajack]

Uh, not everyone has a fuel polishing system or thinks having one is worth the expense.

Or, run your fuel polishing system more often.
Dont forget the change the o'rings on the fuel deck fill caps.

 

[Streff]

Thank you all for the thoughtful input. I finally got my stuff ready & made it to the boat to change the racors. I had 2micron & 10micron filters. I ran the engines and checked the vacuum gauges. At idle rpm, both gauges read a bit below yellow. Despite only running the engines for 103hrs last year, I felt motivated to change the racors based on the vacuum.

Both racors were pretty clean, I mean really clean. I decided to install the 2 micron racors. Then started the engines.. The darn gauges still showed a reading just below yellow at idle rpm. That was surprising. I thought maybe the 2 microns could be creating an issue despite being new. Then I replaced them with new 10micron racors. Same thing.. gauges readings are just below the yellow range. Engines sounded no different than usual.

I am not sure where to go next. Will tackle this in the morning. why are the gauges showing higher reading than usual at idle with brand new racors.

I would appreciate your thoughts and input..

Thank you in advance

Streff

 

[catalinajack]

That would suggest to some that your gauges are faulty cuz those new filters and very likely the 103 hour filters are not the culprit. More likely, you have a restriction in the supply line to the Racors. Rubber fuel lines sometimes separate and collapse inside, not apparent to the naked eye. I wouldn't replace your rubber supply lines. This is good to do as preventive maintenance in the ordinary course anyway. Others here will,be along with other theories.

Thank you all for the thoughtful input. I finally got my stuff ready & made it to the boat to change the racors. I had 2micron & 10micron filters. I ran the engines and checked the vacuum gauges. At idle rpm, both gauges read a bit below yellow. Despite only running the engines for 103hrs last year, I felt motivated to change the racors based on the vacuum.

Both racors were pretty clean, I mean really clean. I decided to install the 2 micron racors. Then started the engines.. The darn gauges still showed a reading just below yellow at idle rpm. That was surprising. I thought maybe the 2 microns could be creating an issue despite being new. Then I replaced them with new 10micron racors. Same thing.. gauges readings are just below the yellow range. Engines sounded no different than usual.

I am not sure where to go next. Will tackle this in the morning. why are the gauges showing higher reading than usual at idle with brand new racors.

I would appreciate your thoughts and input..

Thank you in advance

Streff

 

[OldDan1943]

That would suggest to some that your gauges are faulty cuz those new filters and very likely the 103 hour filters are not the culprit. More likely, you have a restriction in the supply line to the Racors. Rubber fuel lines sometimes separate and collapse inside, not apparent to the naked eye. I wouldn't replace your rubber supply lines. This is good to do as preventive maintenance in the ordinary course anyway. Others here will,be along with other theories.

Initially, I questioned the accuracy of my main engine vacuum gauge then I realized I have a vacuum gauge on the generator filter body and a vacuum gauge on the fuel polisher, all reading zero. 3 bad gauges? Could happen but, I doubt it.

 

[catalinajack]

Agreed, without us knowing how your fuel system is plumbed to the Racors, it will leave us to make assumptions and guesses. I agree, it is highly unlikely that your gauges are faulty, one maybe, but not more than one. And it's not the filters. I think you need to start working backwards from your filter housings. Somewhere there is a restriction. Replace any rubber hose in the supply to the housings first. Generally, this is not difficult and not expensive. Use marine rated fuel hose and new, non-perforated hose clamps.

Initially, I questioned the accuracy of my main engine vacuum gauge then I realized I have a vacuum gauge on the generator filter body and a vacuum gauge on the fuel polisher, all reading zero. 3 bad gauges? Could happen but, I doubt it.

 

[rgano]

I had a boat with the Racors mounted about half way up on the sides of the tanks. They generally read near zero, but as the fuel level got below them, the gauges always rose a few inches of Hg. Perhaps the gauges in question are high in relation to fuel level.

 

[Gabe n Em]

Some fuel pickup tubes have coarse screen filters on the ends. Depending on how accessible they are, I would start by pulling and cleaning those.

 

[catalinajack]

Sometimes that can be the problem but the OP noted that his generator does not have a problem with fuel supply.

Some fuel pickup tubes have coarse screen filters on the ends. Depending on how accessible they are, I would start by pulling and cleaning those.

 

[OldDan1943]

Some fuel pickup tubes have coarse screen filters on the ends. Depending on how accessible they are, I would start by pulling and cleaning those.

"Coarse"??? Things have a way of clogging up at the most inconvenient/dangerous times.
I might consider removing the screens and cleaning the tanks. OR someway of back flushing the screens.

 

[RickyD]

Thank you all for the thoughtful input. I finally got my stuff ready & made it to the boat to change the racors. I had 2micron & 10micron filters. I ran the engines and checked the vacuum gauges. At idle rpm, both gauges read a bit below yellow. Despite only running the engines for 103hrs last year, I felt motivated to change the racors based on the vacuum.

Both racors were pretty clean, I mean really clean. I decided to install the 2 micron racors. Then started the engines.. The darn gauges still showed a reading just below yellow at idle rpm. That was surprising. I thought maybe the 2 microns could be creating an issue despite being new. Then I replaced them with new 10micron racors. Same thing.. gauges readings are just below the yellow range. Engines sounded no different than usual.

I am not sure where to go next. Will tackle this in the morning. why are the gauges showing higher reading than usual at idle with brand new racors.

I would appreciate your thoughts and input..

Thank you in advance

Streff

As noted before, my new gauges read zero uninstalled and some vacuum on installation I suppose due to my set up. So I have a new zero. I have noted the vacuum reading when I clogged my port engine filter. So I set that as my "death" reading. You may want to try a suggested method to determine when your filters are clogged by cutting the fuel supply and see at what vacuum your engine starts to falter. Mark that at your "death" reading. Now your gauges are set for your system. While I have yet to try this method myself, I'd imagine engine rpm may be important here so you may try it several times at different rpms and under load at your normal run speeds. That is what I'm going to do. Having the gauges that mark your suggested max vacuum and highest vacuum reading is very helpful here. So again my Parker T-handle gauges have three needles. One is settable for your max vacuum. One reads running vacuum and takes a tell-tail needle with it and leaves it behind. This way, after a run I can see what the max vacuum was under load and how much space I have before I reach the "death" zone.

 

[Streff]

I appreciate the responses from everyone. Based on the posts, I went ahead & switched the feeding tank from main tank to flank tanks, ran the engines in an effort to rule-in the fuel lines from the main tank as the culprit. The gauges showed the same high readings. This does not rule-out the fuel lines from the tanks but makes them less likely.

There is a common fuel hose that goes to the racors. I checked those 2 hoses and they look fine to the naked eye for what its worth. I will see if I can get the 3-needle gauges that RickyD describes. I think they can be diagnostically useful.

One off the wall observation. Last year with all the disruptions & lockdowns I had Caterpillar perform all the yearly maintenance for simplicity. The gauges read appropriately. However, when I took out the old racors yesterday, I noticed that the top 1.5” or so of the filters were dry and fuel had not reached all the way up the filters. I assume that they did not filled the canister fully. But it begs the question, could the small space without fuel reduced the recorded vacuum on the gauges after last year’s service?? When I changed the racors, I filled the canisters all the way up leading to a but of overflow when tightening the gauges, making sure no air is trapped..thus influencing the reading bs last year. Just speculating of course.

Next step is to take off the common lines leading to the racors and examining them carefully. Then take the boat out and push the rpms and see what happens to the readings.

A simple 30min maintenance task is turning into a multi-day project. Frustrating but still fun to be on the boat for now.

Thanks

 

[RickyD]

I appreciate the responses from everyone. Based on the posts, I went ahead & switched the feeding tank from main tank to flank tanks, ran the engines in an effort to rule-in the fuel lines from the main tank as the culprit. The gauges showed the same high readings. This does not rule-out the fuel lines from the tanks but makes them less likely.

There is a common fuel hose that goes to the racors. I checked those 2 hoses and they look fine to the naked eye for what its worth. I will see if I can get the 3-needle gauges that RickyD describes. I think they can be diagnostically useful.

One off the wall observation. Last year with all the disruptions & lockdowns I had Caterpillar perform all the yearly maintenance for simplicity. The gauges read appropriately. However, when I took out the old racors yesterday, I noticed that the top 1.5” or so of the filters were dry and fuel had not reached all the way up the filters. I assume that they did not filled the canister fully. But it begs the question, could the small space without fuel reduced the recorded vacuum on the gauges after last year’s service?? When I changed the racors, I filled the canisters all the way up leading to a but of overflow when tightening the gauges, making sure no air is trapped..thus influencing the reading bs last year. Just speculating of course.

Next step is to take off the common lines leading to the racors and examining them carefully. Then take the boat out and push the rpms and see what happens to the readings.

A simple 30min maintenance task is turning into a multi-day project. Frustrating but still fun to be on the boat for now.

Thanks

When I ran one tank dry (on purpose) and switched over to my other tank, I had not fully closed off the empty tank. This caused air to get into the Racors and make the engine quit. So when I opened the Racor 900 to see if the problem was the filter even though the vacuum had not reached critical, I had probably 2 inches of air in there. After refilling with fuel, then running, then the engine would quit again, then I look and again 2" air space. It took me awhile to get to checking the supply valve as the culprit as I checked hoses first. If your engine runs and quits then you may have a leak. I don't understand how it would run with air in the system.

 

[OldDan1943]

Upper inch of the filter is dry??????

This happens even if you switch tanks to the fuel manifold?

First I would discuss it with the tech from Caterpillar. You did pay him good money to work on your engine and that includes the Racor filter.

In my feeble opinion, you have an air leak. Could be something simple as a loose line or gasket at the top of the Racor.

Next suspect is the line that leads from the fuel tank manifold to the Racor.
Remove, blow it out or replace it.

 

[catalinajack]

I appreciate the responses from everyone. Based on the posts, I went ahead & switched the feeding tank from main tank to flank tanks, ran the engines in an effort to rule-in the fuel lines from the main tank as the culprit. The gauges showed the same high readings. This does not rule-out the fuel lines from the tanks but makes them less likely.

There is a common fuel hose that goes to the racors. I checked those 2 hoses and they look fine to the naked eye for what its worth. I will see if I can get the 3-needle gauges that RickyD describes. I think they can be diagnostically useful.

One off the wall observation. Last year with all the disruptions & lockdowns I had Caterpillar perform all the yearly maintenance for simplicity. The gauges read appropriately. However, when I took out the old racors yesterday, I noticed that the top 1.5” or so of the filters were dry and fuel had not reached all the way up the filters. I assume that they did not filled the canister fully. But it begs the question, could the small space without fuel reduced the recorded vacuum on the gauges after last year’s service?? When I changed the racors, I filled the canisters all the way up leading to a but of overflow when tightening the gauges, making sure no air is trapped..thus influencing the reading bs last year. Just speculating of course.

Next step is to take off the common lines leading to the racors and examining them carefully. Then take the boat out and push the rpms and see what happens to the readings.

A simple 30min maintenance task is turning into a multi-day project. Frustrating but still fun to be on the boat for now.

Thanks

Fuel lines can look perfect externally and have collapsed inside. Since you have a common hose that feeds both and you have the same odd problem on both, wouldn't logic tell you the problem may lay therein? And such a simple and inexpensive fix to boot. Again, start simple before moving on to the less simple.

I appreciate the responses from everyone. Based on the posts, I went ahead & switched the feeding tank from main tank to flank tanks, ran the engines in an effort to rule-in the fuel lines from the main tank as the culprit. The gauges showed the same high readings. This does not rule-out the fuel lines from the tanks but makes them less likely.

There is a common fuel hose that goes to the racors. I checked those 2 hoses and they look fine to the naked eye for what its worth. I will see if I can get the 3-needle gauges that RickyD describes. I think they can be diagnostically useful.

One off the wall observation. Last year with all the disruptions & lockdowns I had Caterpillar perform all the yearly maintenance for simplicity. The gauges read appropriately. However, when I took out the old racors yesterday, I noticed that the top 1.5” or so of the filters were dry and fuel had not reached all the way up the filters. I assume that they did not filled the canister fully. But it begs the question, could the small space without fuel reduced the recorded vacuum on the gauges after last year’s service?? When I changed the racors, I filled the canisters all the way up leading to a but of overflow when tightening the gauges, making sure no air is trapped..thus influencing the reading bs last year. Just speculating of course.

Next step is to take off the common lines leading to the racors and examining them carefully. Then take the boat out and push the rpms and see what happens to the readings.

A simple 30min maintenance task is turning into a multi-day project. Frustrating but still fun to be on the boat for now.

Thanks