Exhause water flow Cats on a 96 SR 44SB

[gregarious]

I had poor water flow and overheating starboard engine. Cat tech replaced both impellers and they were bad, esecially stbd. Now I am paying lots of atention to cooling flow. In neutral at dle, lots of flow.In forward or reverse at low rpm, hardly any. I saw one post abut bypass but it was incomplete . Any reference out there?

 

[fwebster]

The 440EB doesn't use the bypass system.........your parts list shows a 6" thru the transom exhaust outlet and no underwater outlets.

 

[gregarious]

I do have underwater exhausts and a side outlet for water. There is some question as to what year I have. The serial# is SERP2909H596 but the engines are 95?. And some parts don't show in the Sea Ray dealers catalog until 97. In Any case, the issue is puzzling.

 

[fwebster]

To answer your original question, if you have bronze exhaust outlets that are mounted on the bottom of the boat, then the boat will have a much smaller main engine exhaust outlet located several inches above the waterline. The smaller outlet is an overflow for the underwater outlet. When pressure or water level in the muffler builds, the excess is expelled thru the smaller fitting above the waterline. The amount of water thru the visible outlet above the waterline isn't a definitive diagnostic tool because the amount of water expelled depends upon common physics and the difference in plumbing between the port and stbd...i.e. distance of the runs, the number of elbows or turns etc. The other huge variable in water flow is the condition of both the heat exchangers and the transmission oil coolers.

As long as the 3116 Cats hold 195˚ under load at cruise speed and the temperature doesn't creep past 195˚ as power/load is increased, it isn't likely that you have a problem since you just rebuilt the seawater pumps. One concern in the south is transmission oil cooler restriction on the inlet side. The cooling tubes are very small and grass tends to hang up in the tubes. All the cooling water must pass that point to make it to the muffler and exhaust outlets so if the oil cooler is restricted, water flow will be reduces and the engines may run hot. It is easy to check and fix...........just remove the 90˚ 1-1/4" rubber elbow on the inlet side and clean out the grass with tweezers or forceps.

Oh........your boat was built in the Palm Coast plant in August, 1995 as a 1996 production model, so yes, the engines would have a 1995 date on them.

 

[gregarious]

Ahh, mystery is getting solved. I used an IR thermometer and the starboard engine is 165-170 at idle after a 15 minute 1000 rpm run whereas the guage read 195. Port engine is 180 and the guage reads 160. Now to try at higher rpm but first will check trans cooler Thanks.

Digital replacement gauges or is the sender the culprit? If I replace both what happens to the alarm system?