Sunny32SSR

lovely Lake Cumerland is back to normal summer pool. With it has come quite a bit of floating debris and without strainers I have become a victim of debris causing higher temps.

Both motors were back flushed two weeks ago and quite a bit of debris was cleaned out. I had also changed the impellers but noticed quite a bit of pitting on the housings. As such, first day back out on the water all things were great till we neared the end of the day. The starboard motor began to warm up after running and going to idle. While I can easily manage the issue by putting it in neutral and revving to 2k to bring up the water pressure, I have so far done the following:

- Removed caps for heat exchanger and cleared the debris
- Replaced both sea pump housings with hardin stainless complete with pulley

Back out on the water last weekend and still had the same issue. Starboard motor was giving me the fits. Again, I can manage through the issue but that's not fun! This week I'm having the following completed:

- Back flush again
- Change coolant
- ChangeThermostat (Factory is 160, should I make the change to a 140?)

Again, the warm up happens only after running north of 4k for any distance or when coming of plane from and running speed. Pipes are dumping a constant amount of water, picked the water up from the hose immediately, and manifolds seem comparable from a touch standpoint as I do not have a infrared temp gauge.

I thought about getting strainers but I know after this year we should be back to clear water so it likely may not be worth a 2k investment.

My other concern is that the starboard water pressure is reading nearly 12psi higher than the port and getting up to nearly 35psi running 4k. All other gauges match nearly identically! At idle only the starboard reads about 2psi and the port reads 0psi. Again, seemingly clearly identify a debris issue between the oil and fuel cooler.

I do not have a code reader and before it reaches the shop is there anything else I should be looking at?

Any feedback is appreciated and again this should be an informed post with questions as I have been diligent with my research.

ballz2thewall

Just back flushing isn't always good enough your gonna have to pull both hoses off of the oil cooler and ream out all the holes with a piece of wire and keep flushing with the hose same with the heat exchanger. Leave the 160 thermostat in

Speedracer29

What engine water temperatures are you seeing, and are you sure the gauges, grounds, and sending units are all in working order?

A bad ground will cause the gauge to use the sender as a ground point and register an inaccurate reading. Also, even brand new gauges can be off by 10-15 degrees, and the 160 thermostat is +/- 5 degrees, so a dash reading of 175-180 would not be unheard of.

Do you have access to an infrared temp gun? (Nevermind, I saw the answer after I re-read the original post).

Are you getting any warning alarms?

If no alarm, you aren't hitting the 190 mark. The PCM/alarm doesn't use your temp gauges, so hypothetically you could have a faulty gauge reading of 200, but no alarm because the engine is below 190.

While I agree the difference in water pressure between engines leads one to suspect an obstruction in the seawater loop, I'm always inclined to start trouble-shooting with the easiest, cheapest items I can accomplish without technician intervention..... Gauges and grounds are easier to check/clean than heat exchangers and oil coolers.

Sunny32SSR

I'll have them pull the hoses and fish for it at the oil cooler.

It will creep up to 190 which sounds the solid alarm and cuts RPM to 1k. Only way to get around that is to shut her down, start it again, and turn it up to 2-2.5k and run it till the temp drops. Once the temp drops she's good to go for another run.

Grounds appear to be good from merely looking at the gauges. Haven't tested anything. Water pressure rises as RPM increases, oil pressure increases and temps are similar until extended runs.

I still think it comes down to debris...

Why leave the 160*? Is there a disadvantage to adding the 140*?

smokin' gun

same problem weeks ago ck the main feed hose at the transom on the inside ..very common problem doesnt matter
if your boat is fresh water or salt water .the inside fitting will collapse and restrict the water flow

ballz2thewall

Its definitely debris clogging the water flow thats why your water pressure is high . The motor is programed to run with a 160 t stat if you put in a 140 the motor will run to cool and rich besides youll just be masking the real problem. And if u have debris clogging your coolers you can have no t stats in and the motor is still gonna overheat

ballz2thewall

Yes good point but he would have less water press because then the water would be restricted before the pump

Speedracer29

If you're bumping the 190 mark and going into guardian mode, it's probably not the gauges.

I'll also second what smokin gun said, it happened to a friend last year with his Bravo, right after he put a new impeller in, gave him fits for a couple of weeks before another similarly affected boater clued him in to the transom hose/fitting issue. He didn't have a water pressure gauge though, only temp.

Sunny32SSR

Is this the line I've read on between the transom assembly and the sea pump?

smokin' gun

yes i just fixed 2 more this week same thing ...i do it now whenever i do a motor job .its right there in front of you .so easy to do when motor is out .hell i keep the hose and the little cone fittings in stock