Go Back   Winnipesaukee Forum > Winnipesaukee Forums > Boating > Boat Repairs & Maintenance
Home Forums Gallery Blogs YouTube Channel Classifieds Links Calendar Register FAQDonate Members List Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Display Modes
Old 08-25-2018, 05:27 AM   #1
lfm
Senior Member
 
Join Date: Sep 2003
Location: Alton Bay
Posts: 96
Thanks: 28
Thanked 6 Times in 4 Posts
Default Overtemp only when on plane

Have a 2004 Four Winns with a Volvo-Penta 5.0 GXi. It overtemps when the boat is on plane. Can run it all day plowing around at 25mph.

If I let the boat get on plane, the temperature gauge spikes quickly, so I stop the boat and push the throttle back up, but not let it get on plane and the temp drops almost as quickly as it went up.

Had the impeller replaced in the spring.

Any ideas on where to look for the problem?
lfm is offline   Reply With Quote
Old 08-25-2018, 08:25 AM   #2
tummyman
Senior Member
 
Join Date: Aug 2009
Location: Moultonborough
Posts: 423
Thanks: 59
Thanked 306 Times in 104 Posts
Default

Check to see if any of the water intake holes are plugged.....
tummyman is offline   Reply With Quote
Old 08-25-2018, 09:06 PM   #3
Cal Coon
Senior Member
 
Join Date: Apr 2018
Location: Lakes Region
Posts: 302
Thanks: 102
Thanked 103 Times in 64 Posts
Default

Quote:
Originally Posted by tummyman View Post
Check to see if any of the water intake holes are plugged.....
If water intake holes are good to go, I would check / replace thermostat. Also, if you can, put it on a trailer, and run it on engine ears in the driveway and check the amount of water that is being pumped out. Try this at different rpm's to see if it makes any difference in water flow. I trailer my boat, and start my boat all the time in the driveway, so I have a pretty good idea of how much water gets pumped out as the boat is running, so I would notice if it was less than usual. If you keep your boat in the water, you may not be as familiar, but I would be curious to see if the boat acts the same way on engine ears, as it does under a load.
Cal Coon is offline   Reply With Quote
The Following User Says Thank You to Cal Coon For This Useful Post:
lfm (08-25-2018)
Old 08-25-2018, 09:54 PM   #4
lfm
Senior Member
 
Join Date: Sep 2003
Location: Alton Bay
Posts: 96
Thanks: 28
Thanked 6 Times in 4 Posts
Default

Boats in the water, gonna pull it tomorrow.

Doesnít seem to be tied to RPM, can run at high rpm with the bow up, and it will overheat at the same rpm if I get the boat on plane. Seems to me that it must be able to get good water flow, and wouldnít that indicate thermostat is okay?

Maybe sucking air somehow when on plane?
lfm is offline   Reply With Quote
Old 08-26-2018, 07:34 AM   #5
The Real BigGuy
Senior Member
 
Join Date: Apr 2004
Posts: 569
Thanks: 17
Thanked 161 Times in 102 Posts
Default

I have a Volvo penta (2000) and it has a belt driven raw water pump (in addition to the outdrive impeller) that was replaced for the first time last winter. I didnít know it had more the impeller to pump water to the engine. I guess the impeller must pump to the rwp which pumps to the block. You might want to check that the rwp is working properly.


Sent from my iPhone using Winnipesaukee Forum mobile app
The Real BigGuy is offline   Reply With Quote
The Following User Says Thank You to The Real BigGuy For This Useful Post:
lfm (08-26-2018)
Sponsored Links
Old 08-26-2018, 03:05 PM   #6
Dave R
Senior Member
 
Dave R's Avatar
 
Join Date: Jul 2004
Posts: 2,767
Thanks: 225
Thanked 628 Times in 368 Posts
Default

I strongly suspect you have leak on the suction side of the raw water pump, on a part that's under water if you are going slow, but above water if you are on plane. When under water, it's just another water inlet and the boat will run fine. On plane, it allows air in and since air is vastly less dense than water, this will dramatically reduce the amount of water getting drawn into the pump and the boat will overheat until you slow down and put the leak under water again. The most common place for this air leak to occur is on the end of the hose in the gimbal housing. The hose gets clamped to a plastic nipple and the clamp is loose or the nipple is bad.

When the boat is out of the water, remove the water pump inlet hose and put a garden hose in it. When you turn it on, water will come out of the inlet holes in the drive, but it will also escape from the leak and help you find it quickly.

Last edited by Dave R; 08-26-2018 at 05:46 PM.
Dave R is offline   Reply With Quote
The Following 2 Users Say Thank You to Dave R For This Useful Post:
lfm (08-26-2018), Resident 2B (08-26-2018)
Old 08-26-2018, 07:40 PM   #7
lfm
Senior Member
 
Join Date: Sep 2003
Location: Alton Bay
Posts: 96
Thanks: 28
Thanked 6 Times in 4 Posts
Default

Dave, thanks. I also found this video which hopefully is helpful.

https://youtu.be/uc47zc09RmA
lfm is offline   Reply With Quote
The Following User Says Thank You to lfm For This Useful Post:
Dave R (08-27-2018)
Old 08-27-2018, 08:46 AM   #8
Dave R
Senior Member
 
Dave R's Avatar
 
Join Date: Jul 2004
Posts: 2,767
Thanks: 225
Thanked 628 Times in 368 Posts
Default

I have a Mercruiser Bravo drive (which is a very similar design to the VP you have) and mine was leaking in the same exact place and had the exact same symptoms you described earlier this season. The bravo uses a somewhat different attachment method to connect the hose to the gimbal housing, but a leak there results in the same problem you are having.
Dave R is offline   Reply With Quote
Old 08-27-2018, 09:01 AM   #9
Woodsy
Senior Member
 
Join Date: May 2004
Location: Weirs Beach
Posts: 1,617
Thanks: 52
Thanked 712 Times in 292 Posts
Default

While you are pulling it apart to fix the air leak... replace the raw water pump too. Cheap insurance.

Woodsy
__________________
The only way to eliminate ignorant behavior is through education. You can't fix stupid.
Woodsy is offline   Reply With Quote
The Following User Says Thank You to Woodsy For This Useful Post:
Dave R (08-27-2018)
Old 08-27-2018, 12:42 PM   #10
Dave R
Senior Member
 
Dave R's Avatar
 
Join Date: Jul 2004
Posts: 2,767
Thanks: 225
Thanked 628 Times in 368 Posts
Default

Quote:
Originally Posted by Woodsy View Post
While you are pulling it apart to fix the air leak... replace the raw water pump too. Cheap insurance.

Woodsy
Totally agree with this, the air did the impeller no favors...
Dave R is offline   Reply With Quote
Old 09-04-2018, 03:52 PM   #11
Dave R
Senior Member
 
Dave R's Avatar
 
Join Date: Jul 2004
Posts: 2,767
Thanks: 225
Thanked 628 Times in 368 Posts
Default

Any updates?
Dave R is offline   Reply With Quote
Old 09-04-2018, 07:14 PM   #12
lfm
Senior Member
 
Join Date: Sep 2003
Location: Alton Bay
Posts: 96
Thanks: 28
Thanked 6 Times in 4 Posts
Default

Quote:
Originally Posted by Dave R View Post
Any updates?
Sadly, no. I have neither the trailer or the time, so I took the boat to a marina. Apparently, they donít have the time either because they havenít looked at it yet.
lfm is offline   Reply With Quote
Old 09-04-2018, 09:13 PM   #13
Dave R
Senior Member
 
Dave R's Avatar
 
Join Date: Jul 2004
Posts: 2,767
Thanks: 225
Thanked 628 Times in 368 Posts
Default

Quote:
Originally Posted by lfm View Post
Sadly, no. I have neither the trailer or the time, so I took the boat to a marina. Apparently, they donít have the time either because they havenít looked at it yet.
Bummer. Good luck
Dave R is offline   Reply With Quote
Old 09-10-2018, 09:23 PM   #14
lfm
Senior Member
 
Join Date: Sep 2003
Location: Alton Bay
Posts: 96
Thanks: 28
Thanked 6 Times in 4 Posts
Default

So I got the boat back on Saturday. They flushed every hose in the system and changed the thermostat. No cracked nipple. I ran the boat at planed out at nearly WOT, and the temp never cracked 170.

I donít understand why it only overtemped on plane before, but am glad itís fixed.

Thanks again for the advice.
lfm is offline   Reply With Quote
Old 09-11-2018, 03:32 PM   #15
Dave R
Senior Member
 
Dave R's Avatar
 
Join Date: Jul 2004
Posts: 2,767
Thanks: 225
Thanked 628 Times in 368 Posts
Default

Quote:
Originally Posted by lfm View Post
So I got the boat back on Saturday. They flushed every hose in the system and changed the thermostat. No cracked nipple. I ran the boat at planed out at nearly WOT, and the temp never cracked 170.

I donít understand why it only overtemped on plane before, but am glad itís fixed.

Thanks again for the advice.
The thermostat must have been stuck in a barely open position. That's a new problem to me, oh well, glad it's fixed.
Dave R is offline   Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump


All times are GMT -4. The time now is 06:58 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2019, vBulletin Solutions Inc.

This page was generated in 0.08501 seconds