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Hey Stu,

We got as far as Telegraph Harbour but only a short 3 day and back to Vancouver. I've actually never been to Maple Bay but we'll try and make it happen.

Tom

I hear you Ken. Just for good measure I have appealed the 25% countervailing duty surcharge on the US steel HX and Riser. May as well make them work for it.

Ground # 1..."It's already too expensive!"

Hawk

Thanks Ken, Just to wrap up the outcome I decided that the new water heater replacement was unlikely to be the source of my low rpm and over heat issues. Since the HX and exhaust elbow/riser were potential suspects AND they were likely much more than 10 years old I ordered new one of each from Catalina Direct and shipped to my shipping box in Pt. Roberts Washington. I knew I was going to get banged up with the CDN 30% exchange rate and them 12% CDN tax. But when the CDN border officer said, `You heard about the new countervailing surcharge duties....ugh no.

Add another 25% on top for importing US steel....and while you fork over even more $ we`re supposed to say, Take that Trump!

Anyway, with a friend we installed the new HX and the new ss riser. I put a new flange on as well and the fancy insulating jacket that one must purchase. Frankly the old elbow and riser looked fine but given its age and Stu`s 12 yr replacement I am avoiding a big problem if it broke when underway. Stu`s tech notes were very useful.

Then I was away sailing in Italy on a friends boat so only just this week took the boat out for a test. I thought that if the low rpm under power issue persisted then I was looking at rebuilding the injector pump which is well described by Ron in a tech note. But happily all is just fine...good power at 2500rpm and steady at 165 degrees temp. The problem may have been the HX and perhaps involving the riser.
I`m sailing over the Gulf Islands finally on Monday. Thanks for everyone`s help over the last few months!

Hawk

Ed, no dark smoke, looks normal at idle and at 2200 in gear.

Ken, I ran the engine at 2700 in neutral after I was testing in gear when I could only get 2200 in gear. The darn temp started dropping once in neutral at the higher rpms and got to about 165 and happily stayed there for 15 mins.

Something is not right. Am I correct that if I had an air lock or some blockage it would cause the temp to go up in neutral as well as in gear?

I have to rule out any prop wrap but not sure how that could have happened.

Thanks again guys.
Hawk

Yes thanks, I have immediate flow in the loop through the WH and have several times repeated Stu's method. All hoses that should be hot are indicating coolant flow.

The latest on this yesterday is that for good measure I checked the HX inlet which was clear. I cleared the raw water seacock inlet again which seemed fine ( and the exhaust water discharge has always looked fine).
I burped the system Stu's way and then by running the engine without the manifold cap and revved it up a few times.
Replaced the thermostat 2 days ago with a new 160F which seems fine.

But here's the rub as I mentioned before. I can run the engine in neutral up to 27/2800 yesterday for 15 minutes and the temp is happily sitting at about 165F. BUT when I put into forward gear I can only get the rpm to 2200 with full throttle. AND the temp starts slowly increasing over 10 minutes past 180F+.

Yes, I double checked and marked the throttle linkage location when at full throttle in neutral (2800 rpm) and then again when in gear (maxed out 2200). The linkage was in the same position when at full throttle in neutral and in gear but the max rpms were very different as above.

So it appears that the cooling system is working and I can run at high rpm in neutral with steady 165F. BUT now when put into gear I have diminished RPM in gear and increasing temps.

I have not yet jumped in the water to check the prop. Murky water. But could I have picked up something around the prop coincidentally? I presume that could reduce rpm and cause the engine to work harder?WILL CHECK THIS.
I have not yet changed the two fuel filters. changed them two seasons ago. WILL DO THIS. Could there be an issue with reduced fuel?

The key issue now seems to be why would the engine purr along with cooling fine in neutral at high rpms BUT have immediate diminished RPMs from a max 2900 when in neutral,  down to 2200 with throttle at full AND then the temp begins to increase toward 190 and 200F over about 10 minutes??

Sorry to keep coming back on this guys. I'm at bit of a loss. The water heater replacement went just fine but now this............boats!:)

Keep your thoughts coming ...they are really helpful.

Hawk

Thanks guys,

I guess another test would be to run the engine up to the rpms where the temp was rising past 180F with the new thermostat removed??

Does that make any sense?

Tom

Thanks guys. I'll have to keep working on it...Ron's suggestion and checking the HX. The thing is that all this started after replacing the water heater, which turned out to be the easy bit.
Ken,

Where would I check the temp on the engine when I find a zap thermometer?

Tom

Still at it with a twist.

The thermostat went in fine and appears all well when at lower rpms.
Today I noticed that in gear when put to full throttle the rpm is max 2200. Way lower than normal. Then in neutral it will go as normal up to about 3,000. I checked the throttle assembly and cable at the engine and the little locking nut was loose but I'll have to really assess what going on.

I did see a similar thread here  http://c34.org/bbs/index.php/topic,1704.msg9198.html#msg9198

AND I still experienced the temp moving steadily past 180 when I had the throttle at 2000 rpm which I realized was near the max on the throttle lever (in gear not in neutral) So I've got two non-normal things going on with my departure date looming):

IDeas welcome.
Tom

Thanks Guys. Ron, I'm sure the hoses are clear. I can get immediate liquid out the other end when I put some in.

I'm picking up a thermostat and gasket tomorrow from a Kubota dealer. Ken your new tstat part number was bang on, but they said the gasket part number is now 16264-73270. May want to check that in the USA.

Happily the two bolts came off easily. The tstat has a whitish substance covering the top 3/8ths in. Who knows.

I take it I can drop the new one in the housing filled with coolant, and put the new gasket on. Do I use any gasket goop or no? Then burp again?

Thanks!

Thanks Ken.

I had noticed the old part number changed so your update is very helpful. Hopefully the local dealer has the tstat.
Fingers crossed that the bolts are not a problem. Thanks for the tips.

Hawk

Thanks Stu and Ken,

Reading the Thermostat 101 thread leads me to try replacing the thermostat as someone else replaced their WH and after burping found they also had to put in a new thermostat. I've had the boat 11 years so who knows how old it is. Could be partially stuck so only at high rpms the engine will overheat in 10 minutes as Ron mentioned, which is exactly the case. Also watching the raw water flow out the back it looks normal and certainly should not be resulting in 200F at only 2000 rpm.

So I'll find a thermostat and gasket and try that first. Looks like I need to carefully undo the bolts on the thermostat housing. Anything to be aware of in the replacement job??

Thanks guys

Tom

Still no solution on the over heating.

I put coolant into the pump, filled the hose all good. I warmed the engine up and opened the thermostat petcock so fluid ran out, all good. Ran the engine up to 2900 for several minutes with the pressure cap off of the manifold, all good.
The hose from the thermostat to the manifold warmed up as Ken suggested to check.
The raw water seems to be pumping out the stern exit port just fine and looks normal to me.
BUT up to about 1500rpm all is fine at about 160F but when I put it to 2100 the temp slowly creeps up over 10 to 15 mins toward 200F.

Normally my engine will run 10 hours straight at 2400rpms at 165F. Done it coming down from Desolation Sound several times.

SO one thought is the thermostat which is old...could replace it.
Another thought is a small blockage into or of the HX or possibly the elbow. I had the HX serviced 4 years ago at an alternator shop however.

I'm scratching my head harder now...starting to hurt. :)

Please weigh in with any thoughts/suggestions.

Thank
Tom

Stu,
I did all of that and unfortunately the engine still increased to over 190 over about 10 minutes. normally it will run at 165 for hours at 2200rpm.

Today it starts to move from 160 toward 190 when the rpm's are at 2000. I had it in gear at the dock.

I have not done the pressure cap off and 2500 to 3000rpm option yet.

Any  thoughts?  Anyone?

Many thanks
Tom

Thanks Ken, I did a little more digging through the older "Burping" threads and Wiki 101 so will head down today and give it a try. My raw water intake is clear but that wasn't likely the problem yesterday:)

By the way the new Oldendorfer water pump (last year) is ticking along Ken. Thanks.

Hawk

Stu/Ron,

Finally got the new water heater installed and works well using the shore power and heats well running the engine.

On the first long run I yesterday though I noticed the temp went way up. I then was able to blow out the raw water intake line out the sea cock which has worked in the past, thinking we sucked something up. But the temp was still higher than the normal 165 degrees, pushing over 190+.

Going to give it a go again today and will also check the impeller. Could there be any air issue? I followed Stu's article including adding coolant to the two engine side hoses. ( By the way Thanks Stu!!)

Hawk