Cat 3126 shut down while running

R

relentlesss

Member
Mar 27, 2016
34
Middle river MD
Boat Info
1996 Sea ray 450 Dancer 3126 cats garmin plotter raymarine radar
Engines
3126 Caterpillars 420hp
Our Starboard motor lost all power. While cruising at 2300 rpms. I throttled back slowed to a stop. Restarted motor. Checked high idle rpms PUT boat back in gear and got right up on plane with no other issues. Any advice would be helpul. I think it may be the racor filters but they were just changed 30 hrs ago. Thanks in advance.
 
A couple or possibilities:
As you changed the racor - look for bubbles around the element; an air leak will shut the engine down. I would thing, however, restarting would not be immediate in this case.
Intermittent electrical issue with the fuel solenoid. There is a relay and other "simple" wiring that operate it up to the start switch.
 
I had an issue like this early on and it was my fuel primer sucking air intermittently,it was backing off some from a seated position.Also check the racors.

Good luck
 
Air in a fuel filter, either a Racor or the engine mounted Cat filter would not allow an immediate restart.

A dirty fuel filter doesn't usually shut a Caterpillar engine down immediately. The effect is fuel starvation so your rpms would slowly decrease from 2300, not shut the engine down like turning off a key.

Check to be sure the ball valves on your priming pumps are in the closed position. If the engine shuts down again, stop where you are, leave the ignition switch on and check for voltage at the fuel supply solenoid. I believe on a '97, the fuel supply solenoid is controlled by a little black Bosch type relay ($10 at NAPA) located in the junction box on the end of the engine nearest the bulkhead. Finally, this could also be an injector seat leaking in cylinder #1,#2 or #3. Cat engines have a fule gallery t hat supplies all the injectors....when an injector seat leaks combustion gasses by the injector, the fuel gallery fills with air and effectively shuts down every cylinder after it. The definitive test for this is to connect a clear hose on the fuel return line and run the engine under load. The clear line will have bubbles in it if an injector seat is leaking. This repair isn't terribly expensive but it will require a Caterpillar mechanic because it requires a special reamer to reseat the injector.

The other thing here is that the engine does restart. I'd run it a while longer and see if it happens again and if it does, how frequently then perhaps the cause will be more obvious.
 
FW quote " I believe on a '97, the fuel supply solenoid is controlled by a little black Bosch type relay ($10 at NAPA) located in the junction box on the end of the engine nearest the bulkhead."

This was the case on my boat. Identical problem, very intermittent and I spent a lot of money replacing other parts.... And per FW & Barlow in NZ it turned out to be a 12-volt relay, I bought at my nearest auto parts for less than $10 or CAT will sell you the same relay for $25+ dollars. I replaced both, carry spares but have not had the issue since the new ones went in.
 
As always thanks for the responses. The relay does make alot of sense. That is the only thing other then the solenoid that i think would shut the engine down like that. I think it almost shut down on me the day before. It stumbled a lil but didn't shut it down and it did not do it again. until the next day when it shut it all the way down.

Thanks again
 
Solenoids are $200+ apiece.... I bought 3 and still had the issue, I then spent under $10 at Auto Parts and have not a problem since. Mine got so bad I made a fused jumper wire with alligator clips on each end and would jump from 12v positive battery to the positive side of the fuel solenoid.
 
Prosideus said:
Is this a relay that will work as a replacement for the OEM component?

https://www.amazon.com/Cole-Hersee-..._SR160,160_&psc=1&refRID=HCAPY3FXBMCV0TR5JZFE
Click to expand...
81735_x600.jpg

NO..... It looks like this. Pull out your old one and take it with you.
 
David,

Caterpillar made a design change between 1996 and 1997. If your engines have a rectangular contol box with a hinged top on it located near the where the transmission joins the engine and easily seen looking down on the engine, you do have the little black Bosch type relay pictured in post #9. Earlier engines do not have that control box but have a couple of the relays like the one you mentioned in your post #8. Since you have a 1996, I'm thinking you have the ford starter solenoid type relay in #8.
 
That is correct Frank. I do not have the box. Is it ok to pick up the ford starter solenoid from an auto store to use instead of the Cat replacement part? Cat part is $80.


Sent from my iPhone using Tapatalk
 
UPDATE ...Took the boat to the Hyatt Regency/ River marsh Marina. In Cambridge. 3 hour trip one way. Motor shut down twice. Shut all engines down went to engine room. Replaced both of the Bosch relay's. One on engine engine. In square control box above where trans and engine meets. As stated by earlier. No other problems since.
 
You must log in or register to reply here.

Forum statistics

Threads
113,167
Messages
1,427,705
Members
61,078
Latest member
96SR40EC
Back
Top