R29 Yanmar Running Hot

[aroett]

Hello,

Looking to purchase a 2010 R29 with 260hp Yanmar.
During sea trial observed the engine to be running hot. After running WOT for a couple minutes the temp was 212F. Slowed down for a bit and then went WOT again and temp got to 216F. (WOT = 3800rpm, 100% load)

From the forums it seems normal temp should be around 205F at higher rpms.
-Thermostat, impeller are new.
-No obvious debris in raw water lines.

Obviously I don't plan on running WOT for long periods of time - but:
Is this a concern?
Anything else you recommend checking?
Could over-propping be causing this?

Thank you for any help you all can provide.

 

[Katmat]

May need to check the heat exchanger for blockage. Could have parts from a old broken impeller.

 

[BB marine]

Inspect the reverse gear cooler for debris, replace the impeller and find out why WOT rpm is low. The WOT rpm should be 4000 rpm. Is the bottom fouled? If after theses checks you still experience a over heat. I would recommend a full inspection of the raw water system ( thru hull pick up to the discharge at the exhaust riser )

 

[Brian B]

Check the coolant level in the heat exchanger. Remove the cap when the engine is cold, level should be just below the cap. Do not go by the level in the overfill bottle.
Few years ago I assisted in the replacement of a thermostat in a 4BY 180, the thermostat needed to be compressed when being installed. If not installed properly it will not function as it should.
If you have access to the aftercooler remove the end caps and flush it out.

 

[CaspersCruiser]

........Remove the cap when the engine is cold, level should be just below the cap. Do not go by the level in the overfill bottle........

Truth! The dang overflow bottle has “Min” and “Max” line molded into it. Don’t use them! Period. Take the coolant cap off on top of the engine when it’s cold and fill it to the bottom of the filler neck.

 

[Scottfree]

I have the same boat. In fact it is the yellow one one you see on the Tugnuts home page. It runs hot at WOT, I have a new impeller, flushed the engine, cleaned the intake and run with the engine hatch open (in the Missippissi and Alabama at 100 plus degree weather). The boat is a trawler. it has a displacement hull NOT a semi displacement hull (oxymoron). Ranger has tried to market it much faster than it is truly capable of. The Yanmar 6BY is a very capable engine and does amazingly well within the design limits of the engine. When stressed it overheats. If you want a fast boat then buy one. This is a Trawler. I have taken mine over 10,000 miles and it has performed flawlessly. The Yanmar is the most cost effective engine made. The switch to other engines is purely a profit driven or marketing initiative. Do your research on hull speed and it will make a lot more sense. AND do not buy an Outboard Trawler, think quarter mile tank! Buy the 2010 its an awesome boat if its what you want.

 

[aroett]

Hello,

Thanks for all your input.
The boat is being sold by company familiar with these boats and engines so I assume they know all these things to try.
We'll see....

If after checking all these things, it still runs approx. 10-degrees hot at WOT and only able to get to 3800rpm at 100% load. Engine rated for 4000rpm at 95% load.

I obviously don't plan to run at WOT very often - so do you think this is an issue?

Thanks again!

 

[aroett]

Hi. Still trying to assess why this 2010 R29 is running hot. We have an accepted offer to purchase boat and we like it, but this worries me. The dealer selling it has tried for a week to fix it, but no luck. The following was done recently:
-New impeller
-New thermostat
-New heat exchanger
-Checked all raw water system

-2550 rpm for 10 minutes – 210deg 73% load
-Up to 2800rpm for 12 minutes – 208deg 80% load
-Up to 3800rpm for 2 minutes 216deg max rpm
-Drop to 3400rpm for 12 minutes 216deg 85% load
-Drop to 3000rpm temp dropped to 210deg within 2 minutes and held steady. Zero alarms tech said ran extremely smooth and was very happy with performance.

Is this an issue that needs fixing right away or will affect the life of the engine?
Any input would be greatly appreciated. Thanks.

 

[j&lgray]

The advice and wisdom provided in this thread is spot on. Follow these leads.

I had a 2012 R-29 for two years for the specific reason of doing the Great Loop: 5,800 miles in 10 months. An amazing adventure that the R-29 was perfect for and we did not have any mechanical issues. What is the water temperature you are in? In Puget Sound where the water is 45 to 50 F year round, the boat ran 10 degrees cooler than running in 80 degree water.

I have also had a great conversation with a master Yanmar tech at Mastry Engine Services in St. Petersburg - a Yanmar owned company. What I learned is the Yanmar engines run hotter than other engines by design. These are BMW blocks and marinized by Yanmar. Well designed and manufactured. The ECM (electronic control module) keeps a record of what the many sensors in the engine detect. A Yanmar tech will have the proprietary software to read the ECM and also do software updates. Make sure your new-to-you engine is updated.

 

[knotflying]

Hi. Still trying to assess why this 2010 R29 is running hot. We have an accepted offer to purchase boat and we like it, but this worries me. The dealer selling it has tried for a week to fix it, but no luck. The following was done recently:
-New impeller
-New thermostat
-New heat exchanger
-Checked all raw water system

-2550 rpm for 10 minutes – 210deg 73% load
-Up to 2800rpm for 12 minutes – 208deg 80% load
-Up to 3800rpm for 2 minutes 216deg max rpm
-Drop to 3400rpm for 12 minutes 216deg 85% load
-Drop to 3000rpm temp dropped to 210deg within 2 minutes and held steady. Zero alarms tech said ran extremely smooth and was very happy with performance.

Is this an issue that needs fixing right away or will affect the life of the engine?
Any input would be greatly appreciated. Thanks.

Wow, the seller did all that work and you still have an option to back out? As mentioned the Yanmar does run a bit hot, but usually at WOT. How loaded up is the boat. That will affect RPM. Was the prop checked? Is it the correct pitch? The only other culprit could be the raw water pickup being somewhat clogged. Also, what size is the hose and fitting for the raw water. They have been known to be a bit undersized, hence restricted water flow. Additionally, if the raw water for the head and raw water washdown are coming from the same strainer it has been known that they are the culprit for sucking air into the strainer and less water flow to the engine. Does the strainer look full with no air when at WOT?

 

[BB marine]

The thru hull pick up sizing should be checked, reverse gear cooler inspected, after cooler removed and inspected, the exhaust elbow where the raw water is discharged into the exhaust checked for restrictions.

I question the engine load percentages. They seem high for stated RPMS. I recently started a thread here on TugNuts


viewtopic.php?f=2&t=17591#p115617 There is a post from SkookumR29 that is the same boat has yours. Based on his numbers your boat is still operating 10 degrees higher than his normal.

Quoted from his post "Another data point that should be considered is coolant temp. At my normal cruising speeds (1800 to 2800 RPM) we run from 192F to 198F which is normal".

Look at the temperature operating parameters of the Yanmar what is the set point for the alarm? What is the present ambient water temperature of the sea water that is cooling the system. The engine operating temperature will change with sea water temperature. Example: My C26 in Lake Michigan with ambient water temperature in the mid 60's will operate at 192F 3800 to 4050 rpm, In the inland river systems mid 70's water temperature I have seen 198F, In the Florida Keys high 70's low 80's water temperature 202F and climbing after a couple of minutes of operating at the higher RPMs. I don't operate there long but I'm still 7 F drees lower than the maximum operating parameter. I see close to 10 degrees difference in operating temperatures in my engine between cooler water and warmer water. My point to this is if your issues are operating in cooler waters and you are seeing close to maximum temperature operating parameters.If you operate in warmer waters you will have issues. It would be something I would want to address before owning or using the boat. The engine should be capable of operating properly though the full range idle to WOT without exceeding the manufactures temperature operating parameters in sea water temperatures @ or below 86 F.

 

[dgiles]

If you are not getting max RPMS at WOT you are most likely overpropped which will cause more heat and load throughout the RPM range. Now, could be a dirty bottom which can be cleaned to fix the issue, but if this isn't the case, the pitch needs to be adjusted. Yes it is hard on an engine, yes it creates extra heat and yes it burns more fuel.

 

[aroett]

Hello all,
Thanks for the responses, appreciate it.
Some more info / answers to the feedback:

-Boat is in BC so ocean temps are cold (<50F)
-The work on the engine I mentioned was done by seller last year prior to selling so there was other issues with engine
-Engine has 1000-hrs on it
-Bottom is clean & overall the boat is light. There is a dinghy on back but no gear on boat
-I did get a diesel inspection done and he too recommended getting prop checked. I just can't really change pitch before I own it!
-The inspector hooked up to the ECM before and after the test drive - and there were no engine codes

So by the sounds of it, the issue does need fixing asap and first places to start are the prop and continue to look at raw water supply. This all makes sense - I just worry that these 2 things check out OK and still have an engine that runs hot!

Cheers.

 

[Newf]

I may have missed it in your posts, so you may have done this already but have you made comparison checks with a heat gun. That some temperature shots with an infrared gun, especially near your engine temp sensor and compare them to your gauge temperature over a range of RPM's.

Many times the gauge temperature will not be the "actual" engine temperature. This may not be the case with this engine but it's worth checking out.