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Old 07-26-2015, 10:44 PM   #1
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Default Starboard vs port manifold temperature?!

Hi!

Today, after about 6 miles running around 3k rpm, I docked and with no particular reason I start looking for engine and cleaning it. I noticed that starboard exhaust manifold and elbow is so hot that I can't stand my hand for more than a couple of seconds while those at port side is only a little warm and I can stand my hand on it as long as I want.

Looking for my manual cooling diagram I can't find a reasonable explanation for this huge temperature difference... any idea?

V6 alpha 2
Salt water cooled
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Old 07-27-2015, 02:52 AM   #2
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Use a IR thermal sensor and take readings of both manifolds. If one is hotter than 160 F its to hot and should be inspected and may need replacement.
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Old 07-27-2015, 11:06 AM   #3
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I'll buy one this week but I suppose it's higher since 160F = 71C and 71C is tolerable, as far as I know...

Any way, I'll post results when tested.

Ty
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Old 07-27-2015, 11:27 AM   #4
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Also take a reading of the coolant hoses feeding each manifold to see if there are being feed water of the same temp.
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Old 08-06-2015, 12:07 PM   #5
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Here are readings made today morning.

After 20 minutes engine running (5 heating, 10 inside marina at low speed - marina floodgates still closed because of tides :\ - 5/10 minutes stopped and then 5 minutes flushing with fresh water) I observed:

1. starboard side is about ~20F to ~30F hotter when compared with port side
2. the hottest point is in starboard manifold, on stern section (the colder zones are located at stern half of elbows)
3. starboard hoses are always hotter than port hoses (but became even hot after engine stop, which means water is circulating while running, I think)
4. all starboard side of thermostat housing assembly is hotter than port half, and the stern zone is the hottest zone (where water get inside, coming from engine, right?)

Temperatures (F) - picture label:
1A: 145
1B: 159
2A: 112
2B (manifold - not gear lub hose): 129
3: 125
4: 119
5: 126
6: 120
7: 124

Another detail: when I press the biggest cooling hose (the one which links thermostat housing assembly to engine water circulating pump) I hear some kind of cracks... could it be parched and losing rubber? It seems nice from outside!

Also, took some pictures of water flushing from propeller (while flushing circuit with fresh water). Do you think the flow seems ok (the tap was half open)?

Also, took some pictures of water coming out from propeller (while flushing circuit with fresh water). Do you think the flow seems ok (the tap was half open)?

Another question (out of topic): I always flush cooling circuit with alpha ii all down because I saw we must do it (in the internet). But, if NOT engaged, can it really cause damage if we run engine while in trailer position?

Thank you
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Old 08-06-2015, 01:26 PM   #6
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It would be more effective to measure the temperatures after the engine has completely warmed up and is running. Possibly running under some RPM. The temperatures you're reporting seem way too cool.
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Old 08-06-2015, 04:18 PM   #7
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To start with the good news none are over 160 F. As shrew said I would prefer taking temp after running on plane for 30 minutes.

My comments.

#6 is the raw water supply and I would expect this to be under 100 F put since it runs across the top of the engine it may be getting heated up.

#7 depending if you pointed between the t-stat and hose #6 you can get a mix of engine water and raw supply so the number will be low. Need to point directly at t-stat of intake manifold where t-stat installs.

2B is the power steering hose but you temp is actually the manifold which makes sense with the reported number.

#3 is the water supply to the starboard manifold and #4 is for the port. The starboard is 6 degrees hotter which is not uncommon.

Not sure I understand where 1A and 1B are pointing too as they seem to be the same but have different readings.
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Old 08-08-2015, 04:23 PM   #8
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Thank you both!

Shrew: you right! Made it today.
Moment: 2b arrow is wrong. Is pointing to manifold. 1b is all poiting to hot manifold. Line is dotted and dashed because is poiting behind riser.

Now I have good and bad news.

Good news: temperatures on open running are good. Ran 15 minutes @3,5RPM and no hot spots unless one single spot on starboard manifold which shown 163F but it's inside thermometer error margin. Returning to marina few minutes ago, I made 30 minutes @3,5RPM (my regular speed) and temperatures are even lower (water temperature is lower now).

BAD NEWS:
I'm being towed because I can t engage forward speed. After retur to marina I decided to stop nearby to take advantage of the end of the day. Can t engage forward anymore. Ask for marina help and they are towing me. :/
When I engage quicksilver 3000 throtle forward, engine does not engage and propeller keep stopped. I try to engage backward and I can't. Is stuck. If I use middle button I can I put throtle to forward and backward.
If I try to engage, forward do nothing. Backward is stuck.
In fact, after backward engage, it was always difficult to engage forward again. I must to give a smal touch to red button and throtle so I can engage forward again. Now it fails completely!

Do you think this is a quicksilver 3000 throtle adjustment issue or a lower unit issue? :S
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Old 08-08-2015, 04:40 PM   #9
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So exhaust temps are fine but now a shifting issue.

Let me see if I am following you.

With the center button pressed to disengage the shift cable you can move the shifter into both forward and reverse positions, correct?

When trying to shift into forward the shifter moves into forward but no forward gear, correct?

When trying to shift into reverse the shifter will not move into that position, correct?

Sounds like the shifter or the drive has failed. Try disconnecting the shift cable at the shift bracket on the starboard elbow and see if the shifter works. Then disconnect the lower shift cable and see if you can shift the drive by pushing and pulling on the end of the cable.
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Old 08-08-2015, 05:06 PM   #10
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I forced reverse and it looses but Now i can shift forward and reverse, with red or middle button pressed but drive does not engage anyway! Damn!
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