10 day vacation on the boat now leads to questions about next mechanical steps

[Gimme Time]

Port engine ran a little warmer than I'd like and even brought the Sea Ray audio alarm which is almost impossible to hear. Note to self (Replace alarm with louder alarm). The port engine had been running about 5-10 degrees warmer than the starboard and I replaced the water pumps on both engines last fall after a small leak was detected. 11 years old and what ever I do to one engine I do the same to the other so they stay on the same schedule.

I have been getting a little more smoke and now think it's probably time to pull the Turbos, After coolers and heat exchangers for cleaning. Had the valves adjusted in 2010 by Cat wanting to make sure I kept the engine up to specs? I'm thinking I should have a Cat tech come in and check the engine over to see what their recommendations would be and provide an estimate. Anyone have an idea what kind of cost to pull the above parts and pieces and have them cleaned & checked thoroughly?

I am also getting a little more vibrations now that I feel I should be so it looks like it's time to have the engines & shafts aligned properly. Was reading a couple of weeks ago about vibration isolators which are the motor mounts settling over time with the weight on them and in some cases you just can't adjust them properly anymore as they should be replaced. Reading about alignment and looking at the shafts indicate I'm probably getting more movement than I should so it's time for that process as well.

Your comments and knowledge are always of interest,

 

[markrinker]

How many hours on these engines?

 

[fwebster]

John,

Overheating, smoke and vibration are most likely from 3 different causes.

Smoke on these engines usually indicates increased load, probably caused by fouling on the prop and shafts or by an intake air restriction. Attack these items on the basis of doing the cheapest first........ Clean the intake air filters ($15 K&N cleaning kit) , then either dive the boat ($3/ft) or haul out and pressure wash the hull and check the running gear for growth ($10/ft), and finally, if you still have sooting, have Cat remove and clean the aftercoolers (roughly 12 hours labor, but could be more due to restricted access on the AC). If you have the aftercoolers cleaned, ask Cat to check the turbos and they may need to clean the exhaust side, but normally turbos don't need anything but clean oil and clean air.

Overheating is most likely caused by the heat exchangers getting some build up in them, assuming you have verified that the strainer and hoses are clear and the sea water pumps are fresh. Heat exchanger problems usually begin with the engine temps creeping up when the engines re under load then it gradually gets worse until you have to reduce RPMs to control temps. The fix is to remove the tube core and acid wash/rod it ($85 for o-ring kits plus about 8 hours labor assuming you can remove the core without removing the heat exchanger body from the engines).

For the vibration, alignment is relatively easy and inexpensive, and if you haven't done it recently, so you should begin there. If it is straightforward and if your technician is experienced, you can do a simple alignment in about 1.5 hours. Get some ham handed clutz without experience and it can take a day. From there, analyze (don't measure it! - just feel it) the frequency of the vibration you feel....an engine vibration transmitted to the stringers will have a frequency about 2.5 times that of a shaft induced vibration. My boat is 16 years old, 1300 hours, and I don't get any engine vibration, so I think worn out engine mounts is unlikely and you are more than likely dealing with a shaft or prop issue. Engine misalignment will cause the prop end of a shaft to whip, usually more at higher RPMs than at lower rpms and, sometimes, harmonics between the engines will make the vibration seem to occur at different rpms at different times. If you do a haul out for pressure washing and haven't done it recently, you should also consider having your props trued and balanced ($700). My guess is that the engine alignment and truing the props will handle your vibration.

Hope that gets you started..............

 

[Kon Tiki]

I completed a complete tear down of my cooling system this spring, I was chasing a cracked end cap on one of the heat exchangers. This lead to replacement of all hoses and a dip of my heat exchanger cores as mentioned by Frank. I was pleased and or surprised to see that a fair amount of zinc by product on the sea water side had accumulated, and then on the freshwater side, the petroleum based by product of the anti- freeze had generated a slime coating. The color change on the heat exchanger was significant after acid cleaning. All be it the hoses were in fair to good shape, I found that at least 50 percent of the hose clamps were corroded to the hose, no real mechanical clamping action was left. The engines have 1200 hours.

My temperatures were in the 180 - 185 range before the job, now they stay right at 180 under all loads and most speeds.

Hope this helps.