Official Caterpillar3116/3126 Thread

Here are my warm engine idle speeds. The port is low and has been like this as long as I owned the boat. The throttle has a little play in it, so I need to tighten that up first.

550 vs 620...probably need to bump both up to 650. Both run smooth as is.

39A5357E-AF16-4DE8-AB45-1D8171950040.jpeg
 
I think I have finally dialed in the idle and the other good news is my fuel knock is gone! The Aetna digital tachs are awesome, but I am so OCD that it drives me wild that the idles are off slightly, with the stock gauges ignorance is bliss.

 
Nicely done! I doubt you could get two engines any closer.

The Aetnas can be a bit off on initial start up when cold per the manual...
 
dtfeld said:
I didn't think CAT turbos are field rebuild able. I was under the impression you had to swap em out. Curious what you find out.

Did you get a gauge on them?

Curious, if the pressure was low prior to removing the aftercoolers? Without black smoke I'm still not convinced you have a problem. I would expect lower power and black smoke from the lower side.
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Pressure was low on both sides pre-cleaning, the port came up after all the winter work so that's where the discrepancy is.

I have a good gauge coming that I'll put on, but with the complete unknown as to what the PO had CAT do to fuel delivery I've bit the bullet and scheduled a technician to come out and run the boat with me. I figure worst case it costs me a few hundred bucks and they say all is well, or we fix it.

3-4 psi delta is annoying and I'd love to see it come up but the 850-900* at 2200 isn't sitting right
 
Carver370 said:
I think I have finally dialed in the idle and the other good news is my fuel knock is gone! The Aetna digital tachs are awesome, but I am so OCD that it drives me wild that the idles are off slightly, with the stock gauges ignorance is bliss.

Click to expand...

nice! I have mine down at 700 at the moment. Anyone know what ZF recommends as max idle shift RPM? I like 730-750 idle for smoothness but I'm cautious of transmission wear if that's too high
 
Strecker25 said:
nice! I have mine down at 700 at the moment. Anyone know what ZF recommends as max idle shift RPM? I like 730-750 idle for smoothness but I'm cautious of transmission wear if that's too high
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The transmissions will be fine up to about 1000rpm. 725 to 750 should be your idle target.
 
dtfeld said:
Here are my warm engine idle speeds. The port is low and has been like this as long as I owned the boat. The throttle has a little play in it, so I need to tighten that up first.

550 vs 620...probably need to bump both up to 650. Both run smooth as is.

View attachment 104091
Click to expand...

im surprised yours are so smooth at that RPM. We rattle quite a bit below 630 or so
 
Has anyone flushed the raw water side? Is there a set up of parts needed ? do i need to disconnect the pump and exhaust? is it worth using barnicle buster? i have a new to me 450 with 890 hours
 
Saverio said:
how do u do it?
like your winterizing or do you disconnect the pump and exhaust and let it circulate?

Saverio
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Interested to hear this as well. If you pump into the inlet right before the fuel cooler (where the seacock hose comes in) and then disconnect the exhaust elbow feed and redirect to your supply bucket that should create a loop I believe.
 
I wrote a check, but he did let it circulate at least an hour per side.... He said the bubble reaction was the indicator of how long to leave it running. It was very reactive at first and then slowly died down. He had a rubber stopper that he inserted into one of the lines he disconnected and had a brass barbed connector with the line from the bucket/pump connected to it.
 
How many of you guys have condensate drains on the aftercooler? I’ve looked at others in for sale ads and it seems hit or miss.

I fired the engines and checked ours out mainly because I was curious - at idle the valve is open and there is a slight vacuum so air is being drawn in. Of course as the turbo builds positive pressure it closes and the bilge is a relatively clean environment so bypassing the airsep doesn’t seem like a major problem, it just seems odd that it’s normally open until a load is put on the engine.
 
Strecker25 said:
How many of you guys have condensate drains on the aftercooler? I’ve looked at others in for sale ads and it seems hit or miss.

I fired the engines and checked ours out mainly because I was curious - at idle the valve is open and there is a slight vacuum so air is being drawn in. Of course as the turbo builds positive pressure it closes and the bilge is a relatively clean environment so bypassing the airsep doesn’t seem like a major problem, it just seems odd that it’s normally open until a load is put on the engine.
Click to expand...

To my knowledge, I dont have them on my engines...
 
IMG_6752.jpg IMG_6753.jpg IMG_6755.jpg IMG_6759.jpg IMG_6760.jpg IMG_6762.PNG IMG_6766.jpg Odd thing happened this weekend. I've been working on replacing the dash panels with all new gauges, all the switches, installed a stereo, installed Raymarine Axiom, etc.

The gauges are about 95% of they completed, had 2 lights that weren't hooked up and finally this week was ready to check it all out. Head out Sunday evening to the local restaurant, runs great, notice a few of the gauges are not quite right, hang dockside for a few hours, listen to some tunes and then decide to head home. First odd thing....the Axiom is reading 975ft when it's about 6ft, a few of the port gauges are way off (lights off too) and it takes a few times of messing with the Axiom to get the depth right.

I immediately notice most of the port gauges are off, most noticeably the oil pressure seems low, but everything is fine. Throttle up to 1300rpm and I swear I can hear an alarm coming from the bilge, oil pressure still low on port engine. come down to idle and the alarm goes off. Head down into the engine area, no oil anywhere, nothing out of the ordinary and the 2 gauges on the engine(s) are OK.

Throttle back up to 1500 and I swear there is an alarm. Get back to the dock, all is well, everything was ok, no issues. Now here is something odd but the details are fuzzy because I was fixated on the alarm and gauges. I'm 99.9% sure when i hit the switch to turn off the engines the port one turned off as usual but the starboard would not turn off. I tried the switch several times and it just kept running. I turned off the navigation lights and the engine shut off.

Get up this AM, power everything completely down and start everything back up. Oil pressure on gauge looks OK, go for ride and it's fine for about 20 min to when we get to a no wake zone, idle for 10 min and when it's time to get up on plane again I hear the alarm from the engine area (again at 1300rpm and up) and the port oil pressure gauge is low.

I dunno, I want to think it's an error in the rewiring of the dash, replacing all the gauges and the switches. The back light for the dash isn't working, 1/2 of the gauges (port side) are whacky but absolutely everything runs OK, bilge is clean and I want to think everything is OK other than the gauge and wiring.

Can faulty wiring for the oil pressure gauge cause an alarm? Do these 3126 even have an alarm that would be in the engine area??
 
You are right........the problem is in the switch wiring from when you replaced the switches or the panels There are a lot of wiring connections to make and it is very easy to connect the wrong wire to a switch terminal. Do you have a wiring schematic?

Look for a loose ground wire that is causing the systems monitor to give you a warning with less than full voltage on oil pressure or over heat. ZF transmissions also have a transmission over heat alarm.
 
fwebster said:
You are right........the problem is in the switch wiring from when you replaced the switches or the panels There are a lot of wiring connections to make and it is very easy to connect the wrong wire to a switch terminal. Do you have a wiring schematic?

Look for a loose ground wire that is causing the systems monitor to give you a warning with less than full voltage on oil pressure or over heat. ZF transmissions also have a transmission over heat alarm.
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You know Frank, you are one impressive wealth of knowledge!! It was a ground. I'll be running it this weekend but so far during the inspection I think we got it.

Thank you!!! Definitely saved me some time looking elsewhere.
 
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