Is some water in the bilge expected, or an obvious problem?

[ShoalSurvivor]

Re: Is some water in the bilge expected, or an obvious problem?

What temp range should I expect? What does the themostat actually control?

 

[bruceb58]

Re: Is some water in the bilge expected, or an obvious problem?

Water did NOT flow evenly out of both sides. If I rev it up a little, more water comes from both sides.

That is normal. Same reason that one manifold will always be a little warmer than the other too.

 

[MarkSee]

Re: Is some water in the bilge expected, or an obvious problem?

One of the guys with access to the Merc. repower tool might be able to look up that engine s/n but the normal parts look-up site:
https://webapps.brunswick.com/literature/literatureSearch.do doesn't find that s/n
but serv man #25 6a-28 shows your raw water cooled setup:
Boatinfo - Mercruiser Service Manual nr. 25 - 1998-Up - GM V6 Engines

Maybe I wrong thinking you engine should have a 160 degree stat and not 140 but by what I see you should have a 160 degree thermostat which means that below 160 degrees and the stat closed, then whatever water is inside the engine keeps circulating without exiting. Once the temp hits 160 the stat should open and the warmer water is allowed to exit with new water entering. So you should be seeing temps around 160 at the housing with the stat open.

Here's a pretty nice link where you can see the basics of the flow of both a raw(open) water cooled and closed cooling system then click on the button to see how the flow changes when the stat opens. Note that some setups may slightly differ where water hits the exhaust system to exit but should help you.
http://www.boatinghowto.com/content/how-boat-cooling-systems-work-240/

Mark

 

[alldodge]

Re: Is some water in the bilge expected, or an obvious problem?

Engine is a 4.3 Alpha I Gen II. The original was also a 4.3, but had a cracked head and replaced 2-3 years ago with the 4bbl 4.3 engine.
drive SN: 0L102679 1.63R is stamped in, but 1.81R is hand written next to it.
Transom serial # OL517680
Engine S/N: 90004747

View attachment 216221View attachment 216222View attachment 216223View attachment 216224

Reading previously the issue of port and starboard water gave me the impression this could be a twin engine install. Seeing that was my incorrect assumption I wouldn't worry so much about the impeller. Sorry to point you in that direction.

 

[ShoalSurvivor]

Re: Is some water in the bilge expected, or an obvious problem?

Well, I bought new impeller. This boat just saw it's first saltwater, so maybe a 2+ year old impeller is not a big deal. But neither is changing it . So please advise how often an impeller should be replaced.

It ran fine last weekend with no signs of overheating, so I think I'm going to:
1) leave the impeller alone this week (unless advised otherwise).
2) dry it out and launch it (without starting) to see if any water appears. (already ruled out leak while running with muffs)
3) closely monitor temp gauge and measure with IR gun before and while running.


Other stuff:
There are two blower vent holes in the stern. one is connected via coil hose to an inline blower, and then ends down above the bilge.
The other side has about 10" of coil hose, but is not connected to anything. Is this by design: intake from one side; pumped out from bilge bottom to other side? Or should both be attached to blowers, and both run down to above the bilge, in case the stern ever gets swamped again? Should I run with blower on, or is it just needed before starting?

What's the expected operating temp for this engine, or is there a range. Given above, is 160 the max I should see? Is there any way to know if the thermostat is open or closed? (temp of water outflow?) Should the engine warm up to 160 at idle, or should the idle temp be lower? I assume more throttle/load generates more heat...

I greatly appreciate all of the feedback! Thanks guys!

 

[Fishermark]

Re: Is some water in the bilge expected, or an obvious problem?

There are two blower vent holes in the stern. one is connected via coil hose to an inline blower, and then ends down above the bilge.

That's normal and the way it should be.

 

[alldodge]

Re: Is some water in the bilge expected, or an obvious problem?

Well, I bought new impeller. This boat just saw it's first saltwater, so maybe a 2+ year old impeller is not a big deal. But neither is changing it . So please advise how often an impeller should be replaced.{/Quote]

General practice is every two years

It ran fine last weekend with no signs of overheating, so I think I'm going to:
1) leave the impeller alone this week (unless advised otherwise).
2) dry it out and launch it (without starting) to see if any water appears. (already ruled out leak while running with muffs)
3) closely monitor temp gauge and measure with IR gun before and while running.

Leaving the impeller alone for now should be good, replace it next season.

Other stuff:
There are two blower vent holes in the stern. one is connected via coil hose to an inline blower, and then ends down above the bilge.
The other side has about 10" of coil hose, but is not connected to anything. Is this by design: intake from one side; pumped out from bilge bottom to other side? Or should both be attached to blowers, and both run down to above the bilge, in case the stern ever gets swamped again? Should I run with blower on, or is it just needed before starting?

The hoses are installed as designed, as you said they push air in one side and blow out the other. They are low because fuel vapors are heaver then air.

What's the expected operating temp for this engine, or is there a range. Given above, is 160 the max I should see? Is there any way to know if the thermostat is open or closed? (temp of water outflow?) Should the engine warm up to 160 at idle, or should the idle temp be lower? I assume more throttle/load generates more heat...

I greatly appreciate all of the feedback! Thanks guys!

Temp should run at 160 (based on previous post, have not researched) at idle once run long enough to open thermostat. The engine will run hotter but should not exceed 180 degrees at WOT. Only way to know the thermostat is open is your temp gauge. This being said a temp gauge is not always that accurate.

 

[Utahboatnut]

Re: Is some water in the bilge expected, or an obvious problem?

Im pretty sure you should be running right around 145-150* as its a carb and not fuel injected. The FI engines require a higher t-stat they like to run a bit warmer for FI efficiency. As stated you will have one riser top that is warmer than the other its just how they are at least in all the mercs ive owned. you should be able to keep your hand on the top of the riser without it getting burned, as a rudimentary test. your temps should be a bit higher at idle as there is not as much water flow at 600 rpms as say 4000 so thats normal. yes one hose is fresh air induction the other sucks the heavier gas fume laden air out of the bilge that is correct. As for the water intrusion(possibly) issue sometimes water can be trapped and when you take off in the water the bow rises so much that trapped water will finally run back to the bilge giving the sign of a possible leak. try and get the bow up as high as possible now so you can eliminate that as a possibility. You may need to trim up your drive a bit so your skeg doesnt bottom out on the concrete. Whats the black stuff under the skeg in the picture?

 

[Howard Sterndrive]

Re: Is some water in the bilge expected, or an obvious problem?

I'm not sure if it was determined if this was Gen I or II, but on my Gen II, I ended up pulling the engine and relaunching the boat to find the leak. On mine it was the Y pipe lower o-ring. I was pretty sure of the general area before hand as I could see it running down when a mirror was placed behind the engine, and the water was warm meaning it had been through the engine.
But, I was able to identify about 6 other places water COULD come in.
1. The hydraulic trim manifold - there is a gasket that keeps water from coming in the hose pass-through -I replaced it as it looked rough
2. shift shaft. I forget exactly how, but I think the thick gasket for the upper shaft gear housing would also have to be bad or absent
3. plug in the transom plate housing. There is at least 1 pipe plug closing a hole off.
4. water supply hose elbow where water comes in through the transom plate from the drive impeller
5. Fiberglass and wood transom issues - My 1992 transom all looked like brand new despite message board warnings that this was the most likely spot on my Bayliner.
6. Exhaust -hoses between Y pipe and risers, riser gaskets... manifolds, drain cocks.

 

[ShoalSurvivor]

Re: Is some water in the bilge expected, or an obvious problem?

You may need to trim up your drive a bit so your skeg doesnt bottom out on the concrete. Whats the black stuff under the skeg in the picture?

It's down because it's stored. I lift it for transport. The black spot is just where a little water flowed out when I lowered it.


I used to store my outboard in the upright position. should the drive be trimed up or down for storage?

Thanks for all the info!

 

[thumpar]

Re: Is some water in the bilge expected, or an obvious problem?

Down.

 

[ShoalSurvivor]

Re: Is some water in the bilge expected, or an obvious problem?

Good. Trim down for storage is what I'm doing

Reading the manual, and since I don't have a coolant reservoir, I'm assuming that mine is a seawater cooled model.

Also, I can test the thermostat with an ohmmeter as instructed in the manual. Is it safe to assume that if the temp gauge is not working, it could just be the thermostat (yes, it could be the gauge, too). But the place to start testing is the thermostat -correct?

 

[alldodge]

Re: Is some water in the bilge expected, or an obvious problem?

Good. Trim down for storage is what I'm doing

Reading the manual, and since I don't have a coolant reservoir, I'm assuming that mine is a seawater cooled model.

Also, I can test the thermostat with an ohmmeter as instructed in the manual. Is it safe to assume that if the temp gauge is not working, it could just be the thermostat (yes, it could be the gauge, too). But the place to start testing is the thermostat -correct?

Your correct with testing the thermostat first but you test it in a pan of water on the stove. Put a cooking thermometer in and it should open around 140 for a 140 stat and 160 for a 160 stat. The temp should be on the face of the thermostat.

I store my drive down as well to keep from having the boot stretched out.

 

[ShoalSurvivor]

Re: Is some water in the bilge expected, or an obvious problem?

Here's a picture of my thermostat:


Looks like a thermostat inside of a coupling??? Is this normal, or was it stripped? Which do I remove?

Also, can I simulate sending the specified amount of ohms to the gauge to see of it responds as expected? I don't have a tool for doing that, but im wondering if there's a trick of the trade to test a temp gauge.

 

[thumpar]

Re: Is some water in the bilge expected, or an obvious problem?

That is a sensor not a thermostat. The thermostat is the thing that opens when hot to let the water by and circulate. It is on top of the intake manifold at the front in the housing with the hoses going into it.

 

[ShoalSurvivor]

Re: Is some water in the bilge expected, or an obvious problem?

Sorry, I meant "temp sensor/sender".

I can remove that and test it in water with ohmmeter, per the manual.

I assume that the design is to have a collar mounted to the engine block, and the temp sensor just screws into that (so I should be removing only the inner part (the sensor).

also, what is the other thing just below the temp sensor... it has black and yellow wires attached?

 

[ktbarrentine]

Re: Is some water in the bilge expected, or an obvious problem?

Should I run with blower on, or is it just needed before starting?

There is typically (on most boats these days) a warning label near your ignition switch and/or blower switch that should say something like: Run blower for at least four minutes prior to starting engine and after refueling; Run blower when at less than cruising speed.

I generally run my blower all the time because I forget to turn it off after starting and idling out of the no-wake zone.

(We've had at least two engine compartment explosions at our local lake this summer supposedly because of failure to properly use the blower, coupled with postulated fuel system leaks/vapors... one at the ramp and one near the fueling dock. unfortunately one had fatalities)

HTH! Best of luck....

 

[alldodge]

Re: Is some water in the bilge expected, or an obvious problem?

Sorry, I meant "temp sensor/sender".

I can remove that and test it in water with ohmmeter, per the manual.

I assume that the design is to have a collar mounted to the engine block, and the temp sensor just screws into that (so I should be removing only the inner part (the sensor).

also, what is the other thing just below the temp sensor... it has black and yellow wires attached?View attachment 216251

The one with the Yel and Blk wires is your temp sender to your gauge. The one with the single screw stud is the temp switch which when hot closes and sounds the alarm horn. The temp switch should be set somewhere around 190 to 200 your manual will specify. The temp sender is a variable resistor from 10 to 200 ohms depending on the manufacture.

This would be your general thermostat housing setup
http://www.mercruiserparts.com/Show...r=1937&bnbr=130&bdesc=STANDARD+COOLING+SYSTEM

 

[Utahboatnut]

Re: Is some water in the bilge expected, or an obvious problem?

I said to trim up a little bit if you want to raise the bow a bunch to see if there is trapped water in there, if you crank the bow way way up you will bottom out your skeg. but yes keep it stored down. if you are going to all of the trouble of removing the t-stat just replace it with the correct one and be done with it. they can be a pain to get out and if yours has the plastic collar hold down piece dont break the collar trying to remove the old stat. it has to be in there and doesnt come with the kit. typically you destroy the t-stat getting it out anyway. not always but it does happen especially if its the original one. Also take note of the position of the one thats in there it is possible in some cases to install it upside down.

 

[ShoalSurvivor]

Re: Is some water in the bilge expected, or an obvious problem?

Thank for the clarification. I already trimmed up and jacked the bow up to make sure there was no water in the forward areas.
I'm going to hold on replacing or testing the t-stat and sensors until I can verify whether the temp gauge is working.