Catalina 34

General Activities => Main Message Board => Topic started by: cmainprize on August 16, 2010, 03:01:08 PM

Title: Normal Operating Temp M35
Post by: cmainprize on August 16, 2010, 03:01:08 PM
Looking for some info on the normal operating temp for a M35.  The Manual says normal is 165 to 195.  We usally run around 180 at 2100.  The boat is still fairly new to us and 180 has always seemed a little high for a engine speed of only 2100.  My M25 ran seemed to sit around 170. 
I fried an impeller yesterday just as we entered the point of no return in the marina.  The high temp alarm sounded just as we got into the slip.  Changed the impelller today (what a silly design) and went for a test run.  Lots of water from the exhaust but temp was running at 195 at 2100.  Had to limp it in to keep the temp down.  I was unable to find all the impeller vanes.  I got three out that were jammed in the pump casing and lots of little pieces.  Every vane was torn off the impeller.  I suspect it was on the verge for quite some time.  I was hoping luck was on my side and the rest went out the exhaust.  No such luck.  I will start the hunt for the rest of the pieces tomorrow. 

I was just wondering what temp the other members find there engines run at at say 2100 to 2500 rmp.
I was also wondering if the gaskets on the clean out covers on the HX are reusable once they are removed. 

Thanks for the advice.
Cory
Title: Re: Normal Operating Temp M35
Post by: Jack Hutteball on August 16, 2010, 03:39:21 PM
Cory, mine runs at 165 with rpm of 2600.  Has always run at that temp since new.
Jack
Title: Re: Normal Operating Temp M35
Post by: chuck53 on August 16, 2010, 05:02:45 PM
What's the temp setting of your thermostat?
Title: Re: Normal Operating Temp M35
Post by: Ron Hill on August 16, 2010, 05:25:46 PM
Cory : The normal temp (with a clean HX) is 165/170F. 
You really need to find those other broken impeller blades.  The first place that I'd look is in the 90degree elbow of the exhaust from the Sherwood.  After that you might want to take an end cap off the HX and see what comes out - maybe some blades/pieces will flow out?     A thought   :wink:
Title: Re: Normal Operating Temp M35
Post by: cmainprize on August 16, 2010, 05:41:06 PM
Thanks guys
Not sure what the thermostat is rated at.  I can only assume it is original.  The bolts are still covered in paint.  We are a freshwater boat, I don't think our HX's are as prone to clogging up compared to you salt water guys.  But I have been wrong before.  I will start hunting for the missing blades.  Do you happen to know if I can reuse the gaskets on the HX when I put it back together.  I have no idea what kind of gasket is behind the cover. 

Cory
Title: Re: Normal Operating Temp M35
Post by: Momentum M on August 16, 2010, 06:35:28 PM
Cory...my temp is pretty constent...170 no matter at what RPM.

I've mentioned in a past topic that I was never able to keep the rad's overflow bottle with coolant in it.  I've checked everything that I can possibly think of and I see no sign of where it goes.  This is happening since day one (I bought new) and when I add to the bottle...within days it's gone.   
I've stopped wondering since the rad is always full, the temp @ 170 and doesn't overheat.

This Fall I'll be changing the antifreeze as it's to brown for my liking...even if it check to minus 50 or so.

Happy hunting for the missing parts as I also suspect that you have some restriction since before this mishap your running temp was in the normal range.
Title: Re: Normal Operating Temp M35
Post by: Stu Jackson on August 16, 2010, 07:52:45 PM
Quote from: cmainprize on August 16, 2010, 05:41:06 PM
Do you happen to know if I can reuse the gaskets on the HX when I put it back together.  I have no idea what kind of gasket is behind the cover.

I wouldn't.  Do a search on Sendure and find out about gaskets and HXs.

The ONLY way you'll know what thermostat you have is by taking it off and reading it - temp is stamped on it in degrees C.  The temp of the thermostat will determine your running temp.
Title: Re: Normal Operating Temp M35
Post by: Clay Greene on August 16, 2010, 09:51:00 PM
My bet is that you have impeller pieces in your heat exchanger and that is reducing the water flow.  We had an overheating problem with the M25XP engine in our boat and found four impeller vanes that PO had failed to recover - one in the elbow off the water pump, one in the hose to the heat exchanger and two in the heat exchanger itself.  I would check all three locations.  We also had a bunch of broken zinc pieces and other crud in the heat exchanger that we cleaned out with a Limeaway bath.  Our engine temp went down from 185-190 to 165 where it has stayed ever since, two years later.   
Title: Re: Normal Operating Temp M35
Post by: Ken Juul on August 17, 2010, 04:46:19 AM
If it is the original thermostat it is probably a 160°.  Order or make new gaskets, don't forget the o ring.  There has been a recent thread about Heat exhangers with pictures.  A search should find it.  Pull the hose between the pump and the heat exchanger, take it up on the dock and wash it out with a hose, you may be amazed at what comes out.  Check the 90° fitting out of the pump to make sure it is clear.  Pull the ends off the heat exchanger and remove rubber bits from one end, broken pencil zincs from the other.  Put it all back together and see what happens.  Total time is probably less than an hour.  If you think it needs chemical cleaning try Ron's Lime Away method, it should show up on a search also, been discussed many times.  Don't forget to replace the zinc while your at it.

Title: Re: Normal Operating Temp M35
Post by: Stewartn on August 17, 2010, 03:49:55 PM
"I've mentioned in a past topic that I was never able to keep the rad's overflow bottle with coolant in it.  I've checked everything that I can possibly think of and I see no sign of where it goes.  This is happening since day one (I bought new) and when I add to the bottle...within days it's gone.   
I've stopped wondering since the rad is always full, the temp @ 170 and doesn't overheat."


Same story! 170 all day every day. But the antifreeze disappears from the bottle. NO LEAKS, trust me. If you open the radiator cap on the manifold (engine cold), anti freeze oozes (leaks) out as soon as the pressure cap releases. Asked the dealer and two mechanics. Got double talk. No problem. Just like to know what's happenin' down there. Any clues?
Thx/Rgds
Title: Re: Normal Operating Temp M35
Post by: Ron Hill on August 17, 2010, 04:24:14 PM
M35 engine owners: If you look in your Parts Book that came with the engine, on page 46 you'll find that there are 2 thermostates listed (items 13-1 & 13-2)!  Th differant thermostates are production year dependent.  Both are 160F , but have differant ODs !!

Amazing stuff in those engine manuals !
Title: Re: Normal Operating Temp M35
Post by: Terry Forshier on August 17, 2010, 05:06:14 PM
Over the past 5 months I noticed my boat running a bit hotter than usual. I thought maybe I needed the overfill reserve tank since I did not have one. I also recently had to install the riser for the muffler and had removed some of the antifreeze when I did that. But I had burped the motor and followed others advice and did not think that was the problem.. After all this I kept noticing an increase in the temp. I was checking to see yhe water flow and did notice it seemed less than I had remembered but thought it my inagination as there was water. Finally on a short run I started noticing "steam" coming out. I then saw the temp gauge go to 190 and keep rising. I backed off and thought maybe weeds on the prop. i jumped overboard and took a look. NOPE, all clear. Back on board i turned back toward home port. . the temp kept rising then suddenly the needle just slid back to normal range of 165 or so. I thought well, maybe the thermostat. Continuing on back it again began to rise. this time way up over 200 and even when i slowed it kept pretty high, but backed off some. It appeard that water was coming through but hard to tell leaning over the transome of a 1988. So made it in to dock ok. shut down, took off the orbendorfer face to check the imperller. OK. then went to thru hull , took off the hose at the strainer. Opened the valve. NOTHING>I sucked on the hose, with great sucking i managed a little water. ? not right at all. I took a wire and forced it down the tube and the valve, something crunched and the water came pouring in the hose into the boat. Hooked it all back up and now running with normal temperature. I must have had a barnacle or something like that either nesting in the opening or somehow lodged its self in it. So some times the simplest things.
Title: Re: Normal Operating Temp M35
Post by: Stu Jackson on August 17, 2010, 05:43:15 PM
Terry's right.  See Reply #2 and others here: http://c34.org/bbs/index.php/topic,4458.0.html
Title: Re: Normal Operating Temp M35
Post by: cmainprize on August 17, 2010, 06:01:03 PM
Thanks everyone for the advice and comments
I opened up the HX today and found lots of little impeller pieces.  See picture.  Moved on to the elbow on the discharge side of the pump.  It was jammed solid.  I can't believe it still pumped water.  Hose checked out fine.  Reassembled and tested to 2200rpm while tied to dock for about 20 minutes.  It pumped water like a fire engine.  Engine temp went to about 175.  I think being tied to the dock makes the engine work even harder but it seemed to be back to normal.  It will get a good test run this weekend to be sure.

Thanks Again
Cory 
Title: Re: Normal Operating Temp M35
Post by: Clay Greene on August 18, 2010, 08:54:46 AM
Glad you got it worked out.  Also, nice job on shredding that impeller - that is good and cooked!   :thumb:
Title: Re: Normal Operating Temp M35
Post by: lucky on August 18, 2010, 09:31:26 AM
 cmainprize
I have installed a water strainer on the hose from the pump output to hx.It is about 6 inchs from the pump.If the impeller comes apart the strainer will catch the pieces,also I have not noticed any water restrictions.
Al Landry
Lucky hull #13
1986 c 34
Title: Re: Normal Operating Temp M35
Post by: Ken Juul on August 18, 2010, 12:57:27 PM
Added some pictures of the HX to the Tech Wiki.  Engine Section, Cooling. 
Collected them from various posts on the forum.
Title: Re: Normal Operating Temp M35
Post by: rmbrown on August 21, 2017, 10:19:43 AM
Can anyone point me to the operating temperature range of a Universal M35A(C) in the manual?  I see the original post lists 165-195, which is in line with what I'm seeing, but I keep reading about folks getting 165-175 over the entire RPM range.  I'm seeing about 190 at 2300 rpm and 6.4 kts.
Title: Re: Normal Operating Temp M35
Post by: Dave Spencer on August 21, 2017, 11:35:37 AM
Hi Mike,
Page 5 of the M35A(C) manual states the normal operating temperature is 150 - 170. (Admiral panel notation). This seems low to me. I have a 165f thermostat and I regularly run at 165 almost regardless of the load or speed. I've verified this with a handheld temp "gun". I think the next common thermostat for our engines is 185f. I suspect this is what you have if you regularly see 190. I don't see this as a big deal. I consulted with my diesel mechanic friend and his comment is that 150 is too cool for a diesel to run. I think (and he thinks) 165 - 195 listed by the original poster is much more reasonable.  I would be concerned if you had a 165 thermostat and was running at 190. This would point to another issue with the system in my view.
Title: Re: Normal Operating Temp M35
Post by: rmbrown on August 21, 2017, 12:18:46 PM
I thank you!  I swear I looked all over but missed it every time.  That said, I have a working 160 degree thermostat in a full, burped system, with a clean strainer, a clean thru hull and a freshly boiled out heat exchanger.  I'm currently stymied.  It idled at 160 fine.  I left the marina and ran it up to 2500, near the top of the 2100-2600 cruising range but still in it.  The temp ran up to 185-190 (looking at the gauge, which I have compared to my IR temp gun).  I idled back down to 2300 and kept running (6.3 kts) and the temp eased up a little more.

On my first run with it, I ran it about 2500 for 20 minutes and set the 210 degree alarm bells ringing.  That day I hadn't yet burped it but it adds to my paranoia.

The hunt continues. :)
Title: Re: Normal Operating Temp M35
Post by: KWKloeber on August 23, 2017, 11:06:22 AM
Mike,

I've heard of a situation where the water injection tee became nearly fully blocked with scale and so the seawater cooling flow was way reduced.  Verify that you have full flow to the muffler.

kk
Title: Re: Normal Operating Temp M35
Post by: rmbrown on August 23, 2017, 11:49:52 AM
I definitely have flow at the muffler, and the flow looked good to my mechanic... but without measuring it, not sure how to confirm?

I'm gonna show my ignorance here and admit I don't know where the water injection T resides, though.  I just had the riser and hump hose replaced.  Would that have been open and visible at the same time?
Title: Re: Normal Operating Temp M35
Post by: KWKloeber on August 23, 2017, 11:53:09 AM
The cooling water is injected right above the hump hose, where the 5/8" hose  from your vented loop enters the riser.
Title: Re: Normal Operating Temp M35
Post by: rmbrown on August 23, 2017, 01:33:20 PM
Ah... so replaced as part of the riser?  In that case, it's brand new, so not likely the culprit.
Title: Re: Normal Operating Temp M35
Post by: Craig Illman on August 24, 2017, 05:20:26 AM
A couple more places to check, from my experiences, 1. see if there's salt build up where the raw water enters the heat exchanger, 2. check for any zinc fragments by removing the port end cap on the heat exchanger. It looked like I had good flow too, but a zinc fragment (or two) left from a PO shifted and obstructed the tubes enough to raise the temp at higher RPMs.

Wish I was in fresh water to run the engine up at 185.

Craig
Title: Re: Normal Operating Temp M35
Post by: rmbrown on August 24, 2017, 05:33:39 AM
Craig:

Due to time constraints, I paid someone rather than attempting it myself, but the heat exchanger was just removed, boiled out, repainted and replaced.  I didn't get to see it but the mechanic said it was full of scale and partially obstructed so we both assumed that was the culprit.  As it turns out, it was definitely overdue maintenance but not the root cause.

Re fresh water, my boat is less than a mile from the imaginary fresh/brackish line in the Tar/Pamlico river so I'm fairly fresh... but want to see that temp run way more steady and not vary with RPM, at least within the cruising RPM range. :)
Title: Re: Normal Operating Temp M35
Post by: rmbrown on February 13, 2020, 04:08:05 AM
Because it may help someone in the future... I've been using the boat for 3 years and could always work around the temp fine... 2100-2200 gave me nearly hull speed and I didn't need wide open throttle or to cruise at 2600, but if I tried, the engine would start heating up and as it started to pass 190 without slowing up, I'd slow down.  Since I got the boat, I've increased the size of the thru-hull, the strainer, the hose to the engine, replaced both the impeller and then the raw water pump, I've replaced all hoses so I'm comfortable none are blocked, I've taken apart the heat exchanger and cleaned it out, I've replace the exhaust elbow and riser, I've even replaced the coolant pump (because it failed, not for this reason)...

With any luck, I'm about to take the boat on a 4 month trip in 6 weeks so I brought in a pro.  He spent some time with me going over the engine but ultimately, he had me replaced the coolant cap (I'd pressure tested both the cap and the system) and he cleaned out the (embarrassingly nasty) air filter which was oily and full of insulation dust, and the engine never gets above 165 even at WOT.  Runs like a top.