1996 Volvo Penta 5.0FI SX Cobra temp gauge showing high temps

[Boater_Brad]

Hello,

I recently picked up a 96 Four Winns 200 Horizon DLX with the 5.0FI Volvo Penta motor and an SX Cobra outdrive, The first trip things went well temps read a little over 150 on the gauge and the risers and manifold were running about 110- 120 with an infrared temp gun. Im not really sure if im hitting the right spots with the temp gun cause they seem considerably lower than what the gauge is showing. After the last trip out the gauge shot up to right below 200 when cruising at 3500 rpms. When I bring it backdown to 1000 rpms the temp goes back down to right about 150 on the gauge. When I use the temp gun im still getting between 110-120. I'm under the impression it could be a few things. I recently fixed the stereo and im seeing some surges in the gauges and the batteries are a little old so maybe its not meeting voltage requirements? Also thinking it could be the raw water pump since its seemingly cooling when in no wake zones but on a plane its loosing suction and not bringing in enough cold water. Any thoughts? Am i on the right track?


Thanks,
Brad

 

[alldodge]

Howdy

When was the last time the impeller was replaced?

 

[bajaunderground]

It's most likely the impeller...where was the boat run most it's life? Salt or fresh? if salt, it could be impeller plus a few other items. It could be as you suggest; however, there are easier and more likely explanations? Replace and report back!

 

[Boater_Brad]

Howdy

When was the last time the impeller was replaced?

The impeller was changed March of last year but was only out about 10 times the whole year if that even applies. I was given another impeller ill put that in and give it a try and see how it goes!

 

[Boater_Brad]

Well i pulled the impeller it was in good shape and water was flowing to the impeller. So i put it back in and pulled the thermostat, it was rusted as all hell, so i replaced it and cleaned up the housing. Once I put it all back together I ran it on the ear buds for 5 min and it got up to about 160 so i ran it down to the lake and it started overheating as soon as i got it started. I'm guessing i'm sucking to much air or the impeller isnt sucking water. I was told i should take a look at the oil cooler, because they tend to clog up and cause overheating at high RPM's which was my original issue. Any thoughts? Should I clean the oil cooler and look to see if my impeller is pulling water in?

 

[alldodge]

Yes, being all rusted I would remove the hose from the cooler and back flush. The also back flush the rest of the hoses. When the hose is off the cooler feel around or look up inside to see if there are pieces clogged inside

 

[akaBoB]

Boater_Brad

I just went through this on my 94 caravelle with 5.0FL and SX Cobra. I started with replacing the raw water pump impeller, she was still running 180-200 when cruising 3000-3500 rpm. Next i checked the power steering cool, it was nice and clean. So i decided to back flush from here back to the foot. Luckily the spray nozzle on my hose fit inside the the hose coming up from the transom. I got out and was looking at the foot and put my hand over one side of the intake holes to increase pressure, and low and behold i noticed water coming out up higher from behind the rear cover. I removed three bolts and took the cover off. Here i found water leaking from a small inspection cover with 4 bolts. So this told me this is where air was getting sucked in when i was up on plane. I made a new gasket and put it all back together, and now she runs like i'm used to around 150-160. Lake was 82 today.

I had picked up some clear vinyl tubing and some pvc as described in the vovlo penta overheating diagnostic pdf found on this site, so i could figure out where the air was coming from but didn't end up using it. I can post some pics if needed.

Hope this helps,

akaBoB

 

[Boater_Brad]

Boater_Brad

I just went through this on my 94 caravelle with 5.0FL and SX Cobra. I started with replacing the raw water pump impeller, she was still running 180-200 when cruising 3000-3500 rpm. Next i checked the power steering cool, it was nice and clean. So i decided to back flush from here back to the foot. Luckily the spray nozzle on my hose fit inside the the hose coming up from the transom. I got out and was looking at the foot and put my hand over one side of the intake holes to increase pressure, and low and behold i noticed water coming out up higher from behind the rear cover. I removed three bolts and took the cover off. Here i found water leaking from a small inspection cover with 4 bolts. So this told me this is where air was getting sucked in when i was up on plane. I made a new gasket and put it all back together, and now she runs like i'm used to around 150-160. Lake was 82 today.

I had picked up some clear vinyl tubing and some pvc as described in the vovlo penta overheating diagnostic pdf found on this site, so i could figure out where the air was coming from but didn't end up using it. I can post some pics if needed.

Hope this helps,

akaBoB

Thanks Bob! Ill go ahead and give that a try, I just changed the impeller and i'm back to idling fine but creeps up at 3500 like you're saying. Ill try the back pressure technique to see if i'm getting the same issue.

 

[Boater_Brad]

Well i thought things were getting better but turns out im still int he same boat! Still overheating at idle, New impeller, new tstat, cleaned ports in tstat housing, even ran the motor with no tstat and it still overheats. I also back flushed entire system from manifold back. Checked the oil cooler and the any air leaks from the RWP to the Drive. Nothing seems to have any issues. Im now onto the last culprit, the Manifolds and Risers. How much of a pain are they to take apart and work on? Is it something a novice can handle or should I take it in to the shop? Any other thoughts?

 

[Dan01543]

So I have a 1996 volvo penta 5.0fl motor I have brand new risers and manifolds both sides of the motor. Brand new raw water sea pump.my temperature gauge reads little before 160 degrees. So my risers are hot where I can only keep my hand on it for about 5 seconds. Is this to hot.i have gone through the power steering cooler,inspection plate and new gasket on the outdrive. I back flushed everything I also have a new thermostat. I recently had my outdrive off because I had to do a Gimble bearing and Bellow job I looked all inside my exhaust I found my flappers were laying on the bottom of the white pipe I had to pull those out they were no good and a little melted as of right now my exhaust is completely open all the way down to my foot where the propeller is my cooling system is all Brando new hoses everything was taken apart and flushed earlier in the springtime sor in the springtime so my question is at what temperature should my risers be at because they seem a little hot to me a little too hot I ran the boat over the weekend and did 2 miles up river parked it for 8 hours 2 miles back down river it ran fine it's Stayed a little below 160 on the temperature gauge but when I got back to my slip I put my hand on my manifold risers and they were hot again could only keep my hand on them for about 5 seconds just trying to find out if that's too hot and if I have another problem somewhere or what the temperature of them risers should be after running about 3000 RPMI did crack wide open a few times but backed off to 3000 RPM and maintained there all the way to where I was going on the river. So just trying to find out a temperature that the risers should be at thank you

 

[Lou C]

Well I have the same exhaust as the Volvo but on an OMC Cobra (only difference is the impeller is in the drive) and at idle the elbows are cool enough to keep your hand on (100* F), after coming off plane they will get up to 135* but will cool down after moving at idle for a few minutes. This is the way this boat has always been with a good impeller & non clogged manifolds & elbows. I’m in salt water so we know when they start to clog (after 5-7 seasons or so).

 

[Dan01543]

I got a raw water sea pump and it's brand new I have great water pressure coming out the hose