Dual Engines - one hotter than the other

[RandR]

This has been driving me nuts and I have not been able to find the problem. I have a 2005 3300 I purchased last September, with 67 hours on each engine,(merc 5.0 MPI) last fall it ran fine and I did not notice any temp difference between the engines. Over the winter I had the dry joint manifolds and elbows replaced as well as all the bellows shift cables and impellers. I noticed in the spring, although everything ran great, the port engine would cruise at around 190- 192 and starboard would be around 180 on the gages. I thought it was odd but didn't worry too much until while on a 3 hour cruise at 3200 rpm the port engine alarm went off momentarily, I shut it down to cool then proceeded at 3000 rpm with no further alarms. Return trip kept it at 3000 rpms and no alarms.

Back at the dock I temped the engines with an infared thermometer at 2000 rpms
Port thermostat housing 167deg.(dash gage 185) Starboard 162(dash gage 175)

Port Dry Joint Manifolds 181deg. Starboard 150deg.
Port Elbow 82deg. Starboard 82deg.

I replaced the port impeller, and thermostat and no change,
I checked the power steering oil cooler it is clean
I switched temp the sending units and no change
I switched the dash gages and the port gage did seem to run a couple degrees hotter
at one point when I was replacing the thermostat it went together with a gap and the port engine would not get any hotter than 125deg. I re-seated the thermometer and it warmed up to 185 - I think this tells me that there is not a restriction in the engine

I cant think what else to check? any thoughts? has anyone else had this issue??

Thanks

[mmwjr]

We're both port manifolds 181?

I would run the boat on plane for about 10 minutes and retake the readings.

What drives do you have?

[RandR]

To clarify port engine port manifold 181

Starboard engine port manifold 150

I don't recall what the starboard manifolds were but they were basically close to the port and didn't seem much different so I didn't take note but I can next time I am out

What are the exact areas I should take temps at?

The drives are Bravo 3
Thanks
Rich

[mmwjr]

Originally Posted by RandR

To clarify port engine port manifold 181

Starboard engine port manifold 150

I don't recall what the starboard manifolds were but they were basically close to the port and didn't seem much different so I didn't take note but I can next time I am out

What are the exact areas I should take temps at?

The drives are Bravo 3
Thanks
Rich

Coolant hoses into manifolds, tops of manifolds, tops is risers, exhaust hose coming of risers.

[RandR]

I probably won't get the boat out until the weekend but as soon as I can I will get and post all those temps. There are two hoses that go into the bottom of the manifiold with some sort of check valve the top one is from the thermostat the bottom one is from the intake cold water distribution manifiold that is before the engine circulating pump. I assume you are asking for the temp of the hose from the manifold
Thanks
Rich

[mmwjr]

Do you have closed cooling?

I do not recall ever seeing what you are describing.

Typical is one hose from t-stat housing to a fitting that has a drain plug for winterizing.

Got any pictures?

[RandR]

It is raw water cooled not a closed system. I can grab a picture when I a on the boat. Here is a link to the part from the internet

nexthttp://cdn2.bigcommerce.com/server1500/aba1d/products/121/images/293/22_863786A1__94018.1389904543.1280.1280.JPG?c=2

[mmwjr]

Link does not work

[RandR]

Please try this one

http://www.michiganmotorz.com/images...te_456_272.jpg

The meecruiser part number is 22-863786A

[mmwjr]

Originally Posted by RandR

Please try this one

http://www.michiganmotorz.com/images...te_456_272.jpg

The meecruiser part number is 22-863786A

Interesting not see that before. going to see if I can find a diagram of your cooling set up but some pictures would be nice when you can get them.

[mmwjr]

Did some reading, you have the 3 point drain system. The hose that comes from the t-stat housing is the supply and the one to take the reading on. The other hose is for the drain system to winterize.

[RandR]

Ok so I got to run the boat today. all was pretty good on the dock. Here are the temps after 10 mins idle.
Starboard engine
Starboard side. [port side)
Top of riser 87(83)
Top manifold 186(214)
Hose from thermostat 158 (150)
Top of thermostat 165
Top of oil filter 143
Gage reading at dash 180
Port engine
Starboard side. [port side)
Top of riser 88(87)
Top manifold 188(213)
Hose from thermostat 162(157)
Top of thermostat 169
Top of oil filter 147
Gage reading at dash 190

Problems started after running at 3500 rpm for 20 minutes. Alarm went off so we slowed down and these were the temps
Starboard engine
Starboard side. [port side)
Top of riser 89(92)
Top manifold 209(207)
Hose from thermostat 160(166)
Top of thermostat 170
Top of oil filter 143
Gage reading at dash 185

Port engine - after alarm
Starboard side. [port side)
Top of riser 230. (215) huge difference!
Top manifold 220(216$
Hose from thermostat 160. (165)
Top of thermostat 178
Top of oil filter 213
Gage reading at dash 210 Alarm
Brought it down to idle and the temps came down. Pulled into harbor at 2000 rpm and whe we anchored riser tops were back to 90

I am stumped !!!

[RandR]

So while at anchor I climbed into the eng compartment and pulled one Jose off the fuel cooler and it was clear Also checked the check valve. Water ran out fast but I could not blow back through. Also double checked that the raw water pump hoses were not switched. Not sure what to check next! Anyone else have this issue?

[mmwjr]

Almost all of your temps are to high IMO.

The hose from the t-stat is hot as it should be a mix of water leaving the engine plus cool water from the supply to the housing. No temps should be above 160 - 175 F.

I need to think about this some but both engine are too hot.

How old are the impellers? Have the exhaust been disassembled lately and inspected?

[RandR]

Changed both impellers this spring and the port one again last weekend New manifolds and risers this spring. New thermostat last weekend. All new bellows and shift cables the past spring Stumped!!!

[mmwjr]

When the bellows was done were the water house replaced? I have seen were these have clogged at the plastic retainer.

[RandR]

I don't know. I has the shop do that. I will check with them. It is not noted on the invoice.

[RandR]

Finally got back down to the boat, I talked to the shop and they said that they did not change the hose when they did the bellows. I did some more investigating, pulled the elbows, everything was fine, checked the flappers, also fine. pulled both port engine and starboard engine raw water intake hoses...big difference! the starboard was full heavy flow, the port war half that! Water intake must be the issue. I went to the service manager at my marina and he said he has had several engines with simmilar issues and the cause was some sort of seashell growing inside the outdrive water paths and restricting flow. the solution was to pull the boat, take off the out drive, split the outdrive and clean the paths, repaint with anti fouling paint, clean out the hoses form the outside and re-assemble. the cant do it until next week. I will post if it works! does this sound like the cause???

[RandR]

Finally got it set...I think ........the marina pulled the boat to remove the outdrives. A shell of some sort has grown and attached to the inside of the water passage in the outlive. They removed it and put it back in the water. That engine still runs a little hotter, but no alarms! both the risers are cool at 3500 rpm so at least that was part of the solution. I will pull both drives over the winter and split them to make sure the passages are totally clear and also check the thru transom fitting to make sure there is no corrosion there. Should get me through the next couple months with no issues
Thanks for the ideas and thoughts

[mmwjr]

Glad to here you have improved the cooling. Yes split the drives and check also the water hose on the transom assemblies clog so take a good look there.