Official Caterpillar3116/3126 Thread

If the engine runs ok without the racor and runs ok on the other racor then it has to be the racor. I seem to remember that they have some internal parts like ball on a spring check valve.
 
Have a diesel fuel tank question for the 380DA.
As an aside, now I have both 3116's out of the boat, seems like an opportune time to check the diesel fuel tanks.
Apart from pressure testing (if I remember correctly it's about 2psi needed), are there any other tips or input?
The port and starboard aluminum tanks are over 20 years old. I doubt they've ever been cleaned or tested.
I would strongly consider replacing the tanks while everything is out. Likely would switch to poly and be rid of the corrosion issues.
 
I have swapped around the primer pump and the issue still persists, unfortunately.

I'll have a check on the vent as I've flipped over the selectors and the issue remains. It runs without the racor so I don't know how it could be the vent or the pump. Running out of ideas...and sanity

Have you checked the primer valve (not the pump)? If that is not in the correct position, you will have power loss issues. From memory I believe that the valve "knob" should be in the 90* from the pump to be in the "run" position. It can be a bitch to get to as its on the bottom side of the primer pump assembly.

Additionally, make sure the drain plug is sealed in the bottom of the bowl on the Racor...if it leaks, you'll see the same results. You can see bubbles in the racor bowl if this is the issue.
 
If the engine runs ok without the racor and runs ok on the other racor then it has to be the racor. I seem to remember that they have some internal parts like ball on a spring check valve.

Not quite, it won't run with any racor on it, but does run without the racor.

Have you checked the primer valve (not the pump)? If that is not in the correct position, you will have power loss issues. From memory I believe that the valve "knob" should be in the 90* from the pump to be in the "run" position. It can be a bitch to get to as its on the bottom side of the primer pump assembly.

Additionally, make sure the drain plug is sealed in the bottom of the bowl on the Racor...if it leaks, you'll see the same results. You can see bubbles in the racor bowl if this is the issue.

Yes, I did have a previous battle with that valve knob, but I can confirm it is in the run position.
 
Not quite, it won't run with any racor on it, but does run without the racor.



Yes, I did have a previous battle with that valve knob, but I can confirm it is in the run position.

just to be clear - do you mean it runs OK without the filter element in the racor but still pulling fuel through the racor body, or bypassing the racor completely?
 
If the engine runs ok without the racor and runs ok on the other racor then it has to be the racor. I seem to remember that they have some internal parts like ball on a spring check valve.
The check ball is only there to prevent siphoning back to the fuel tank. There are no "springs". The only air leak areas are the lid gasket and the Tee Handle O-ring. All of the other seals will leak fuel.
@nattydread - If you are seeing the fuel level down in the Racor when the engine shuts down you can be assured air is getting into the system before the Racor. If the engine is shutting down and fuel level isn't dropping in the Racor then something is preventing or stopping the fuel flow. A couple of things to consider -
  • The fuel solenoid Relay.
  • The fuel solenoid electrical connections.
  • The fuel solenoid adjustment into the injector assembly.
  • The eight little plastic check valves silted up in the injection assembly.
  • The siphon tube in the fuel tank partially plugged
  • The fuel hose from the tank to the selector valve and/or racor inner liner collapsed.
 
The check ball is only there to prevent siphoning back to the fuel tank. There are no "springs". The only air leak areas are the lid gasket and the Tee Handle O-ring. All of the other seals will leak fuel.
@nattydread - If you are seeing the fuel level down in the Racor when the engine shuts down you can be assured air is getting into the system before the Racor. If the engine is shutting down and fuel level isn't dropping in the Racor then something is preventing or stopping the fuel flow. A couple of things to consider -
  • The fuel solenoid Relay.
  • The fuel solenoid electrical connections.
  • The fuel solenoid adjustment into the injector assembly.
  • The eight little plastic check valves silted up in the injection assembly.
  • The siphon tube in the fuel tank partially plugged
  • The fuel hose from the tank to the selector valve and/or racor inner liner collapsed.

Even though the engine runs normally with the racor bypassed completely?

I have noticed the vacuum gauge does register when I put a vacuum pump on the engine side to pull fuel into the racor. However, the indicator drops back to zero once the fuel fill the glass.
 
The racor talk hit me thinking I should rebuild mine this winter. I see a gasket kit: https://pro.westmarine.com/racor-seal-kit-for-500-series-turbine-fuel-filters-108524.html

I’d also like to add some drain valves. Are these correct? Ridiculously expensive, as expected: Racor U.L. Listed Brass Shut-Off Ma Turbine Retrofit Drain Valve https://a.co/d/2DrYKMT

anything else I should replace while I’m in there? How about the bowl?

I should probably cap the fuel lines, I’d rather not drain $7 diesel into the bilge. I’ll also shut off the fuel valves
 
I have, use and maintain several agricultural and construction diesel powered machines on my place in Tennessee, so I know how to care for diesel fuel in machinery and storage tanks.

I owned my 450DA with 3116's for 25 years. I chose to buy all my boat fuel from a Valvetech dealer who filtered all his fuel at the point of sale, and I always used the additives I recommended in the "Diesel Management Article" posted in the tutorial section. I changed the Racor elements and flushed the Racor bowls annually and never saw the need to tear the Racors apart and rebuild them.

This isn't to say you shouldn't rebuild your Racors but I posted my experience with them to suggest that you examine yours carefully and be sure you really need a rebuild before you get diesel fuel all over your garage or basement.

The. bowl drain valves are a worthwhile addition and you can find UL rated liquid valves from other vendors online for less that the "pot of gold" Racor asks for theirs.
 
I have, use and maintain several agricultural and construction diesel powered machines on my place in Tennessee, so I know how to care for diesel fuel in machinery and storage tanks.

I owned my 450DA with 3116's for 25 years. I chose to buy all my boat fuel from a Valvetech dealer who filtered all his fuel at the point of sale, and I always used the additives I recommended in the "Diesel Management Article" posted in the tutorial section. I changed the Racor elements and flushed the Racor bowls annually and never saw the need to tear the Racors apart and rebuild them.

This isn't to say you shouldn't rebuild your Racors but I posted my experience with them to suggest that you examine yours carefully and be sure you really need a rebuild before you get diesel fuel all over your garage or basement.

The. bowl drain valves are a worthwhile addition and you can find UL rated liquid valves from other vendors online for less that the "pot of gold" Racor asks for theirs.
The racor talk hit me thinking I should rebuild mine this winter. I see a gasket kit: https://pro.westmarine.com/racor-seal-kit-for-500-series-turbine-fuel-filters-108524.html

I’d also like to add some drain valves. Are these correct? Ridiculously expensive, as expected: Racor U.L. Listed Brass Shut-Off Ma Turbine Retrofit Drain Valve https://a.co/d/2DrYKMT

anything else I should replace while I’m in there? How about the bowl?

I should probably cap the fuel lines, I’d rather not drain $7 diesel into the bilge. I’ll also shut off the fuel valves
https://www.mcmaster.com/fuel-valves/compact-threaded-on-off-valves-for-fuel/
 
I have, use and maintain several agricultural and construction diesel powered machines on my place in Tennessee, so I know how to care for diesel fuel in machinery and storage tanks.

I owned my 450DA with 3116's for 25 years. I chose to buy all my boat fuel from a Valvetech dealer who filtered all his fuel at the point of sale, and I always used the additives I recommended in the "Diesel Management Article" posted in the tutorial section. I changed the Racor elements and flushed the Racor bowls annually and never saw the need to tear the Racors apart and rebuild them.

This isn't to say you shouldn't rebuild your Racors but I posted my experience with them to suggest that you examine yours carefully and be sure you really need a rebuild before you get diesel fuel all over your garage or basement.

The. bowl drain valves are a worthwhile addition and you can find UL rated liquid valves from other vendors online for less that the "pot of gold" Racor asks for theirs.

thanks gents. There’s all kinds of crud on the turbulator (sp?) thing inside the bowl so it seems worthwhile to do

Frank, I followed your treatment plan when we took ownership of the boat and after 4 racor changes finally ended up with pink fuel. They were completely black with visible algae strings, so someone didn’t handle the fuel properly in the past.

since then we’ve had no issues and the vacuum gauges do not show any major blockage, but I do see the “junk” in the bowl
 
I assume I can use the same pink antifreeze in these diesels that I used in my previous gassers for raw water winterization? I saw it for $9.99/gallon at West Marine while Lowes has it for $4: https://www.homedepot.com/p/PRIME-GUARD-128-fl-oz-Ethyl-Alcohol-50-F-RV-Antifreeze-95806/314176973?

Ethyl alcohol is a no-no. You want to use propylene glycol in engines, that’s the west marine pink. They’ll take about 7-7.5g each

as to why it’s not recommended, I’ve always heard it eats seals and rubber and such which there is plenty of in the raw water path. Whether that’s true or not, who knows
 
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I plan to change the oil in the next couple of weeks. From reading this thread and others it looks like I want this oil

https://www.grainger.com/product/ROTELLA-Diesel-Engine-Oil-5-gal-Size-33GP56

Is that correct? If correct where does everybody buy it?

I switched to T1 this year. I bought it by the gallon online from Walmart, it was the cheapest by far and had free delivery. There was a discussion a few pages back about how cat now recommends DEO in place of SAEO but I figured lots of folks have had good luck for decades with T1
 
But, Shell has had some problems sourcing the additives in Rotella T1 which is why we couldn't find it last year and the prices got stupid for a while. I last checked prices in about June, 2022 when I was in the Cat store in Nashville: Cat DEO-ULSD was $14.50/gal and Rotella T1 in the TSC store on the way home was $20.94/gal.

Suggest you go back and read the re-thread on Caterpillar's new fluid recommendations (dated in early 2022). DEO is RATED CJ-4 Caterpillar's current recommendaton for 3116 and 3126 engines) AND Rotella T1 SAE 30-40 is only rated CF-2

The CF-2 rating is for normally aspirated (non-after cooled) compression fired (diesel) engines. CF-4 thru CJ-4 ratings are for after-cooled diesel engines.
 
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