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| Overheating on Plane https://www.smwebhead.com/phpBB3/viewtopic.php?f=2&t=6386 |
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| Author: | Marcs220 [ Sat Aug 14, 2010 9:05 am ] |
| Post subject: | Overheating on Plane |
Has anyone out there heard of this one and maybe have a clue on what the problem may be? Put the boat in the water and left dock. Boat was fine all the way thru the no-wake zone. Once thru, gave the boat throttle to geton plane and minutes later the boat overheated. It actually melted the bellows (rubber boots) on the exhaust. The local marina thought impeller and sure enough it was damaged. They cocmpletely flushed the cooling channels twice and changed the impeller (and the melted bellows) and tried it out and it still overheated was given throttle. Next they replaced the thermostat and still no luck. Finally the circulation pump was replaced and still the motor overheats once given any throttle. The marina also did a compression check on the motor and said it was fine. It is the 5.0 GL, SX V-P outdrive model. Also, this is a raw water system. The oil also looks fine after the overheat. A couple of guys at two different marinas suggested the cooling systemm is pulling in air rather than all water?? |
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| Author: | JDW250 [ Mon Aug 16, 2010 3:18 pm ] |
| Post subject: | Re: Overheating on Plane |
The cooling system could be pulling air through rather than water. Not sure what year your boat is, but I have a 2005 VP. The VP operator's manual I have covers a broad range of engines, from 3.0L to 8.1L. On page 85, there is the following caution statement: "When re-installing the blue cap on the fresh water flush hose, tighten it by hand, then tighten it 1/4 turn using a wrench. If the cap is too loose, air may be sucked in, causing the engine to overheat, resulting in damage." You also may want to do a search in this forum on engine overheating. I know I have read of other boaters with overheating problems caused by a miriad of issues. That may be a quicker way to get some additional insight. |
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| Author: | Marcs220 [ Mon Aug 16, 2010 3:26 pm ] |
| Post subject: | Re: Overheating on Plane |
Thanks for the good info. My boat is a 2002 and has the VP 5.0 GL with SX outdrive. |
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| Author: | TX H210SS [ Mon Aug 16, 2010 6:40 pm ] |
| Post subject: | Re: Overheating on Plane |
Have you checked the water pick up grill at the lower unit.....i had been using the tube flush attachment at the engine since I thought it was easier (not)...my motor never ran hot so never thought anything about probs, but when I hooked up the muffs to the lower unit it pushed globs of dead grass out the sides of the grills. I was amazed at the amount - there's no grass where I boat and it was old stuff from the prior owner apparently. Now i look to make sure I see daylight from one side of the grill to the other. |
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| Author: | qweedqwag [ Mon Aug 16, 2010 10:36 pm ] |
| Post subject: | Re: Overheating on Plane |
Man I wonder if they got all the impellor pieces out, I would start pulling hoses and taking a look. The blue cap is a good suggestion really that could be it also if you use it, the lower unit check is also a good check. Are the repairs being done by a FW dealer. Good Luck, Mike |
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| Author: | Graham R [ Tue Aug 17, 2010 5:46 am ] |
| Post subject: | Re: Overheating on Plane |
As well as possible debris/ blockage in the lower unit, ALL the cooling water passes through a power steering fluid cooler at the rear of the engine. That could be partially blocked, allowing enough water through at idle but restricting it at higher engine speeds. Also, when on the plane the upper portion of the outdrive/ transom shield is out of the water; a damaged water hose could cause the symptioms; in water at idle it could not such air in, but on the plane when out of the water it could suck air in. The water seal between the outdrive and the tilt assembly could cause the same effect; make sure the 6 nuts are tight ( 50 ft/lbs). You also need to ensure the hoses from the thermostat housing to the manifolds are clear, plus of course that the manifolds and risers are not choked up with rust debris; restrictions in these may mean water flow is insufficient above idle. Graham. |
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| Author: | TX H210SS [ Tue Aug 17, 2010 10:57 am ] |
| Post subject: | Re: Overheating on Plane |
Trying to not be judgmental here, but you have mechanics and you have part changers......why did they swap the circ pump? Sounds to me they are throwing parts at it to see what happens. The impellor is a no brainer - the oil change is a MUST regardless of how it looks - i also would swap the oil in the drive since if exhaust was so hot it melted bellows it surely kicked up temp on the drive. Them saying the impellor was damaged pretty much means it flew apart....they may have done all this, just questions I would have....did they remove the water lines from the impellor to the therm housing and examine for blockage? Two possibilities in my mind (sure there are more)....the impellor failed due to lack of water supply, which pretty much takes you back to the pickup grill at the outdrive......or.......the impellor failed since it had not been changed and wore out sending debris all thru your cooling system and you now have a blockage. As mentioned before -i would start pulling water hoses and examining them for blockage.....actually, if it got that hot they may need to be changed anyway. |
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| Author: | Marcs220 [ Thu Aug 19, 2010 11:21 am ] |
| Post subject: | Re: Overheating on Plane |
The grills looked clear. The marina that started working on the boat was not a FW dealer (my brother had the boat and went to the nearest marina fearing the worst) and after they changed out the impeller, flushed the cooling system, then changed the thermostat and couldn't find the prob, I took the boat back as I felt the same way, that they were just throwing parts at the problem hoping for a fix. My brother and I actually pulled the circulator pump off and replaced it. This was a waste of cash as the old one is likely fine. At that point I decided to bring it to a FW dealer I have used in the past. He also stated that it was highly unlikely it was the circulating pump. He borscoped up into the intakes and took a quick look at a set of 'bushings' and said they looked clear. I suspect there is a blockage somewhere in the system, but choose to let the professionals deal with it. Thanks again everyone for the great feedback. this forum is great! Happy boating. Hope to be out there myself soon, before summer is gone! M |
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| Author: | walke464 [ Wed Jun 01, 2011 8:14 pm ] |
| Post subject: | Re: Overheating on Plane |
I have this exact same issue. I can go through no wake and have no issues but as soon as I go over 3200 RPM the engine light goes off and the engine overheats. I took it to the dealer and they replaced the bellows and other tubing from lower unit, this didnt' do anything. They replaced the Impellers last year, no issues. The dealer wants me to bring it to them again, any ideas from you all? |
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| Author: | Winter Sux [ Wed Jun 01, 2011 8:52 pm ] |
| Post subject: | Re: Overheating on Plane |
As a marine tech, Often when I deal with overheating issues, I use my thermo-laser gun. This will pin-point the hot spot causing the overheat. Some of these repair places need to get with the 90's,,,if you get my drift. Ask them about this,,,,after all,,,it's YOUR money. |
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| Author: | walke464 [ Wed Jun 01, 2011 9:02 pm ] |
| Post subject: | Re: Overheating on Plane |
This is the dealer we are talking about too! What do they do, have the make it overheat to test it? |
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| Author: | LouC [ Wed Jun 01, 2011 9:03 pm ] |
| Post subject: | Re: Overheating on Plane |
The main things with an open marine cooling system is that you have to have adequate water supply in (intake screens, hose from transom to impeller, impeller and housing) and adequate water flow OUT (thermostat opening all the way, manifold/riser passages not clogged, exhaust not blocked by melted flappers from previous overheat). I start with the impeller, check the hose from the transom to the thermo housing for restrictions, check the thermostat, and the housing for rust in the passages, check the manifolds for heating when on plane. If the manifolds get too hot for you to hold your hand on them, then they could be clogged. You need a better diagnostic process to narrow down causes. If you melted the rubber exhaust hoses that points to a lack of raw water flow. When you start the engine, the thermostat is closed and raw water bypasses the engine block and goes right out the exhaust. Then when the thermo opens, the cir pump then sucks the raw water into the block and it exits out the thermo and then out the manifolds. An infared heat gun can help with testing. |
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| Author: | WarEagle17 [ Wed Jun 01, 2011 10:06 pm ] |
| Post subject: | Re: Overheating on Plane |
Graham R and LouC have great suggestions. I have a 2001 298 Vista. My mechanic was on my boat today fixing the same problem. It had new impellars recently put on and still overheated. The problem....exhaust manifolds were clogged with debris. The water was not circulating properly. Therefore, the water would continue to get hot causing the engines to overheat. He cleaned them out and "presto", the overheating problem solved! |
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| Author: | waynen [ Thu Jun 02, 2011 3:27 pm ] |
| Post subject: | Re: Overheating on Plane |
My 2003 twin 5.0L 280 overheated on plane when I first bought it. We chased and chased and chased. Even had a bunch of clear hoses on the starboard engine. Port engine was always ok and I limped home a couple times on just one. The final solution was to add 1" vertical drive extensions to both drives to lower the pickups in the water. At full throttle it was ok, at idle it was ok. Seems that at 2900 RPM in a "just on plane" condition the sensor for the depth sounder (mounted ahead of the water pickup of the engine on the hull) caused an air pocket to develop in front of the engine at "just the right speed" I lost a whole summer of boating due to this. Finally Four Winns sent A Volvo Field Rep down with his computer and after much testing (including the clear tubing for all the hoses) we got it fixed and it's been good ever since. My question would be what else was done to the boats? Any modifications that would result in non laminar flow at any speed. The sensor on mine was only 1/4" high and tapered to the high point. One would think it couldn't cause the issue.......it did. Wnenn |
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| Author: | pet575 [ Thu Jun 02, 2011 4:45 pm ] |
| Post subject: | Re: Overheating on Plane |
I'm on board with the issue being in the exhaust manifolds/risers. Was what I thought of when you said the impeller was damaged. I'm betting on a blockage in that area. |
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