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1999 Volvo Penta 4.3 GL overheating

bf5595

New member
I hope someone is able to give me a little insight as to what my solution would be,

I have a 1999 4.3 GL that is having an overheating issue on the starboard side of the engine. I have replaced the impeller in the sea water pump, the circulating pump, and the thermostat to no avail. I have also pulled the exhaust manifold and riser off that side to search for any clogs, all is well. Is there something that I am missing?

Side note is that when replacing the carburetor a few months ago there were hoses that lead to the top of the valve covers on both the starboard and port side. The new carburetor did not have a receiving port for the starboard hose so we capped it off (this was advised by a local boat mechanic). I don't believe this would have anything to do with it but it does happen to be the side I am having overheating issues.

Any help would be appreciated

thank you,
Brandon
 
I have a 1999 4.3 GL that is having an overheating issue on the starboard side of the engine. I have replaced the impeller in the sea water pump, the circulating pump, and the thermostat to no avail. I have also pulled the exhaust manifold and riser off that side to search for any clogs, all is well. Is there something that I am missing?

Side note is that when replacing the carburetor a few months ago there were hoses that lead to the top of the valve covers on both the starboard and port side. The new carburetor did not have a receiving port for the starboard hose so we capped it off (this was advised by a local boat mechanic). I don't believe this would have anything to do with it but it does happen to be the side I am having overheating issues.

Brandon, more info re; the engine model would be helpful........ 4.3 GL followed by ____????

From what I see, the 4.3 GL-A, B, C and D do not use exhaust risers/spacers. That engine will have exhaust manifolds and elbows only, as seen below.
When you have the elbow off, look closely at the seawater transfer ports. They should be clean and free from rust scale.




20156.jpg




Make sure that the hoses (SEQ #10 and #11) are not de-laminating on the interior, and make sure that the T-stat housing ports (for those hoses) are clear and free of any rust scale.

20168.jpg






As for the crankcase ventilation (hoses from valve covers)..... the hoses will connect to the carburetor's flame arrestor.
I do not believe that a true Marine carburetor (for this engine) will offer a port for a crankcase ventilation hose.


20192.jpg
 
1999 is right around the time when V/P eliminated the OMC design flappers, I wonder if your engine was made before they were eliminated. If so, an overheat could have melted one of them and it could have fallen down and blocked that side of the exhaust. Not highly likely but possible. When you checked the elbows and manifolds...did you see flappers in the top of the Y pipe? It is possible to have a '99 boat with a '98 sterndrive unit....

As Rick said the hoses that connect to the valve covers don't go directly to the carb but rather the brackets that are held down by the nut that holds down the backfire flame arrestor. They are basically there to bring blow by fumes up to the flame arrestor, kind of in place of an automotive PVC system.
 
Volvo Penta had purchased OMC, and was producing Volvo Penta drives by 1994!
Some OMC parts were used in this newly designed cone clutch drive.
By 1999, these would all be Volvo Penta.

In order to zero in on your exact components, it would be helpful if you were to post a complete engine/drive model number.
The 4.3 GL will be followed with additional alpha/numeric characters.



.
 
Hi, thank you all for the help.

The engine is a 4.3 GL PBYC.

There is a flapper on the port side but the starboard side is missing one. I'm not sure if it was there when it first overheated or not. The pin that holds the flapper actually fell down in and I used a camera that a friend had to retrieve it. (by snaking up the port side is when we noticed there was a flapper on that side) I did not see any other pieces though. If the flapper fell in, (assuming it hasn't been removed previously without my knowledge) would that cause an overheating only on one side?
 
The engine is a 4.3 GL PBYC.

There is a flapper on the port side but the starboard side is missing one. I'm not sure if it was there when it first overheated or not. The pin that holds the flapper actually fell down in and I used a camera that a friend had to retrieve it. (by snaking up the port side is when we noticed there was a flapper on that side) I did not see any other pieces though. If the flapper fell in, (assuming it hasn't been removed previously without my knowledge) would that cause an overheating only on one side?

Here is the 4.3 GL PBYC exhaust component schematic.

SEQ #18 is a back-flow-prevention flapper (although they are calling it a seal) and it is listed as NLA or out of production.
There would have been one on each side.
And yes, if one flapper became disconnected and fell into the Y-pipe it could restrict exhaust flow and possibly cause higher temperatures on that side.






12833.jpg





Here is a 3" extended elbow (although they are calling it a "riser") that would raise the elbow's "turn-down point" up off of the manifold by 3".
It is listed as NLA or out of production.
However, you may be able to find an After-market version.

Since the back-flow-prevention flapper is NLA, this would help against any unwanted back-flow caused by a wave surge, etc.

12780.jpg
 
Here is the 4.3 GL PBYC exhaust component schematic.

SEQ #18 is a back-flow-prevention flapper (although they are calling it a seal) and it is listed as NLA or out of production.
There would have been one on each side.
And yes, if one flapper became disconnected and fell into the Y-pipe it could restrict exhaust flow and possibly cause higher temperatures on that side.





12833.jpg





Here is a 3" extended elbow (although they are calling it a "riser") that would raise the elbow's "turn-down point" up off of the manifold by 3".
It is listed as NLA or out of production.
However, you may be able to find an After-market version.

Since the back-flow-prevention flapper is NLA, this would help against any unwanted back-flow caused by a wave surge, etc.

12780.jpg



I’m assuming I would need to remove the outdrive to get to this and see if there is a blockage? Since it would be past the point that the two sides meet up wouldn’t that cause both sides to overheat and not just one? When we ran the camera down there were no obstructions where the two sides met up.

could it be a problem within the engine and not the cooling system?

this is the first boat that I have worked on and I’m very new but would really like to solve this.
 
..........
I’m assuming I would need to remove the outdrive to get to this and see if there is a blockage?

***Try going into this area again with a Bore Scope. Perhaps come in from the bellows side.


Since it would be past the point that the two sides meet up wouldn’t that cause both sides to overheat and not just one?
That would depend on where it ended up resting.
See above ***


When we ran the camera down there were no obstructions where the two sides met up.

could it be a problem within the engine and not the cooling system?
Possibilities:
..... a dislodged impeller vane is stuck within that side of the cylinder block's cooling jackets, preventing coolant flow (seawater).
..... exhaust manifold issue.
..... exhaust manifold and exhaust elbow seawater transfer ports are compromised by rust scale.


this is the first boat that I have worked on and I’m very new but would really like to solve this.
 
https://www.crowleymarine.com/johnson-evinrude/parts/56985.cfm?mdl=UVYH37

those rubber flappers are still available from BRP....
some parts I've gotten from Volvo/Penta that happen to fit my OMC, some I still get from BRP....In fact when I converted my exhaust to the later 2 piece center riser style I used V/P 90* exhaust pipes and hoses to mate the 4" elbow outlet to the 3.5" Y pipe, these same exact parts were also used by OMC but BRP doesn't sell them anymore, but VP does...
You may have to pull the drive off to get the remnants of that flapper out, when I had an overheat it wound up at the bottom of the exhaust housing, I had to use a wire to fish it out. The fact that your starboard manifold is overheating and the starboard flapper is gone suggests it might be stuck in the Y pipe, but make sure that your thermostat housing water ports for the manifolds are completely open. They do neck down from corrosion and I have replaced mine 2x over the 18 years I've had this boat (salt water use).
 
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