Overheating problem, hey bondo!!!

FreeBeeTony · Apr 24, 2004

Last week I tested my newly installed FWC system for the first time this year. Had 2 problems: 1) wasn't shifting properly: fixed by re-adjusting cable 2) Smoke from exhaust (see earlier post) thought maybe it was oil: tested again today and found it only smoked after running hard (on plane ~3000rpm) with radiator cap on tight. Didn't smoke if I left the cap loose. Also noted that when running on the muffs in the driveway, there was a stream of water coming out of the weep hole in the lower unit. Is this normal and I just never noticed it before? Or is it because of the pressure in the hose? I don't put it on all the way. Now for the overheating problem: gets hot after only a few minutes when running at ~3000rpm, temp climbs over 180. When I stop the boat and put it into neutral, the temp climbs to ~210 then cools down to ~160 at idle. Is this a sign of a bad impeller or a restriction? ALso noticed that the hose connecting the H/E to the circ pump didn't feel like it was full of coolant. is it possible I have air in the system and its not circulating the coolant properly? And I am obviously loosing coolant somewhere in the exhaust causing the smoking problem. I am suspecting the block-off plate I installed inbetween the elbow and manifold is not sealed properly. I don't think it's ( the coolant) going back into the engine because it doesn't appear to be hydrolocked, turns over and starts ok. Do I have 2 problems here? A water pump seal problem causing water to exit through the wep hole? And a possible bad manifold? Sorry for the long post........I feel like I should have left it raw water cooled!

FreeBeeTony · Apr 25, 2004

Re: Overheating problem, hey bondo!!!

bump........

dmorley · Apr 25, 2004

Re: Overheating problem, hey bondo!!!

Tony, Don't give up on FWC. I'll assume you have a "fully closed" system where only the risers and exhaust have raw water. I would start cheap. Specifically, if your impeller has not been replaced for four or more years, it's time to do it anyway. The lost coolant, unless you can see it in the bilge, is the big worry. Again, start cheap and inspect the blocking plate between the manifolds and risers. If those look good I've got some bad news for you: the water has to be getting into the cylinders in small quanities. This happened to me because I had the stupid one piece mercury manifolds. The engine seemed to run fine, but when the machinist pulled the heads I could definitly see the water damage. At any rate, run a compression check and if it's bad get at least a valve job (I had my entire engine rebuilt because I suspected an unrelated problem with the oil pump. Finally, don't rule our the possibility of a bad water pump. However, the lack of steam with the cap off suggest that the pressure of the closed cooling system is letting coolant leak past a head gasket.

FreeBeeTony · Apr 25, 2004

Re: Overheating problem, hey bondo!!!

I don't think it's a head gasket. The engine was completely rebuilt last year, including the outdrive water pump. No water in oil or oil in water. Block and manifold is FWC. Engine is Mercruiser 165 IL6. I am going to check the blocking plate first. What about the stream of water coming from the weep hole on the lower unit? Would this point to somekind of back pressure caused by some kind of blockage somewhere?

dmorley · Apr 25, 2004

Re: Overheating problem, hey bondo!!!

Freebeetony, I don't know what the draining at the weep hole indicates and will watch this thread for someone knowledgeable to respond. However, if blockage is your concern you can check for a raw water blockage by briefly disconnecting the discharge line at the riser. There should be alot of water flying out. Secondly, get a bucket to save your coolant and do the same for the heat exchanger return line. I hope it's the blocking plate, because if there is no visible external leak then you and I know that the only other exit for the coolant is the cylinders. Again, if the amount of water is small the engine will run just fine for awhile, but it will quickly trash your valves and at least in my case it didn't show up in the oil.

Bondo · Apr 25, 2004

Re: Overheating problem, hey bondo!!!

Hi Tony,

there was a stream of water coming out of the weep hole in the lower unit.

How much water ??? WHICH Weep Hole ????

And I am obviously loosing coolant somewhere in the exhaust causing the smoking problem

How Much Coolant ???

Didn't smoke if I left the cap loose.

Hmmmm, Sounds like it Could be the Block-off plate.... Does it overheat with the Cap On or Off ????? When you Squeeze the lower hose, with the cap off, Does the fluid move ??? Did you get those hoses rerouted, below the Cap ?????

FreeBeeTony · Apr 25, 2004

Re: Overheating problem, hey bondo!!!

hey bondo.......... There was a strong stream of water coming out of the weep hole on the starboard side of the lower unit. The stream seemed like it was under pressure. Thought it was from the garden hose but if I remember right, the water inlet is not connected to the opening behind the weep hole. I am wondering if this indicates some kind of blockage causing some back pressure to the water pump. I am suspecting the block-off plate causing the coolant leak. Overheats with or without the cap tightened. I am also going to try and raise the position of the H/E. I did squeeze the lower hose and the fluid in the H/E didn't move as much as I thought it would. Would this be caused by air in the system? Now that I am thinking about the position of the H/E: if I was loosing fluid causing the level to drop below those hoses....would this cause the overheat condition?

yoced · Apr 26, 2004

Re: Overheating problem, hey bondo!!!

I am not trying to intrude here Tony, I know you've been working with Bondo for quite a while on this engine, and I am not trying to distract your current search for answers - keep following the current line of reasoning. But if you could help me understand your system - you say you have a 165 IL6, with a fresh-water cooled manifold. A block-off plate is in front of the riser. How is your manifold plumbed? Water in at the front and out at the rear? Is it done with the end caps? Or did you build a special plate under the riser? Or drill a whole in the manifold? thx

FreeBeeTony · Apr 26, 2004

Re: Overheating problem, hey bondo!!!

I did it with end caps (w/ help from bondo). The coolant exits the engine through the thermostat housing (using an automotive housing I got off ebay) into the front of the manifold and out through an end cap at the rear of the manifold to the return of the H/E.

FreeBeeTony · Apr 26, 2004

Re: Overheating problem, hey bondo!!!

bondo.....any ideas about the water coming out of the weep hole? Should I rebuild the water pump? The impeller only has about 20-30 hrs on it.

POINTER94 · Apr 26, 2004

Re: Overheating problem, hey bondo!!!

Tony, I have the same weep hole on the starboard side of my 1988 alpha 1. Its about 1/4 inch and it shoots out a stream at about a 45 degree angle downward. I started mine this past week on the muffs and I had the same thing. I did not have any overheating issues and I had the entire lower unit inspected, lube replaced, impeller replaced and unit aleigned. Could it be the speedo water tube? Kind of strange place for it. I can't find any specific reference to it in my seloc manual. Not sure what it was either, but it seems to be normal on my unit. I'll wait for bondo to chime in..

Bondo · Apr 27, 2004

Re: Overheating problem, hey bondo!!!

Sorry Tony.... Been Busy.... Black-top seasons Starts next Monday.......... I'll go inspect 1 of my drives... the Weep Hole has me baffled at this point..... Just How Much coolant is being Lost ????

Now that I am thinking about the position of the H/E: if I was loosing fluid causing the level to drop below those hoses....would this cause the overheat condition?

Possibly...... Probably...... Any Bubble in the system Could be a possibility...... Try what Don says,+ Pull the Raw water dump hose off the Riser,+ See if there's A Lot of Water, under Pressure There....... If the riser is blocked, Maybe the weep hole will Stop weeping with the hose off the riser....... Another Thought............. Could you plumb in a piece of Clear vinyl hose on the water return to the H/E...... Then you could SEE if the Fliud is Flowing.........

Tony, Don't give up on FWC.

Amen......... You're Engineering,+ Building your Own System ...... There's Going to be Bugs....... But,...... When It's Right, You Built It......... Believe Me...... The Pride will be Worth the Bug Fixing..........

Could you repost your photos..... It'll save me searching for the old post...... Maybe an Up-date, with the repositioned H/E.....

FreeBeeTony · Apr 27, 2004

Re: Overheating problem, hey bondo!!!

I have trouble posting pics on the board. I will send you the pics tonight from home. Haven't repositioned the H/E yet.

kcole683 · Apr 27, 2004

Re: Overheating problem, hey bondo!!!

I beleive the weep hole you are referring to on the out drive is a drain that drains the lower unit when you pull it out of the water. Mine has water coming from this hole when running on the muffs. I think this is normal. But it would not be the first time I am wrong. I think the hole is on the suction side of the impellar and if the hose pressure is reduced momentarily the flow will reduce or stop as the pump catches up to the hose supply. Anyone else???

kcole683 · Apr 27, 2004

Re: Overheating problem, hey bondo!!!

Here is a link to show the weep hole referred to above. Mercruiser lower housing hole

POINTER94 · Apr 27, 2004

Re: Overheating problem, hey bondo!!!

Thanks Spark chaser!!

FreeBeeTony · Apr 27, 2004

Re: Overheating problem, hey bondo!!!

thanks spark-chaser, makes me rest a little easier...seems like there should be a stream of water coming out of that hole!

FreeBeeTony · Apr 28, 2004

Re: Overheating problem, hey bondo!!!

I THINK I FOUND THE PROBLEM! Tonight I repositioned the H/E and raised it about 4 inches. It definitely should be high enough now. The I went to check the riser bolts, and guess what?????? They were loose!!! Boy, was I glad to find that. So now I should have the leak/smoke problem taken care of and hopefully the overheating problem will be corrected by raising the H/E. I tested it in the driveway and it didn't even get hot enough to open the theromstat. And when I squeezed the lower hose, the fluid level rose. Before I raised the H/E, I tried squeezing the lower hose and the level didn't move. I will let you guys know what happens this w/e when I test it on the water! Thanks........Tony

Bondo · Apr 28, 2004

Re: Overheating problem, hey bondo!!!

That's Great Tony....!!!!....

I got the photos... I think Raising the H/E was the Answer to the Over-heat..... You had it Way Low in the pics.....

I went to check the riser bolts, and guess what?????? They were loose!!!

Gettin Late when you put that together the First Time ??????

Overheating problem, hey bondo!!!

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