4.3 mercruiser on 1996 glastron

[Bluemelj]

Purchased 1996 glastron this summer with a 4.3 mercruiser 350 hours took out 3 or 4 times ran well at least it appeared for a first time boat owner. Working through a few problems I have recently noticed.

1. Just noticed oil in the bilge, not a ton but I have cleaned it out and getting a little bit in the bilges when trailored in my driveway, ran my hand under the oil pan and from front to back there is varying levels of oil. Can't find any oil leaking down from anywhere to find a source, any ideas.

2. Last time out engine missed or hesitated while going about 25 to 30 mph, this had not happened before and did it about 3 or 4 times after being on the lake for a couple of hours. I am now replacing spark plugs looked at them yesterday and all 6 were extremely dirty.

3. Water in the bilge, when on the water its trickling down from somewhere between the engine and outdrive but cannot find the source, when hooked up to muffs I see a small drip of water from the exhause manifold but nothing compared to the trickle coming down when in the water.

4. White smoke with a gas or exhaust smell coming from my exhaust and propeller at start up and some at idle, smell is fairly strong, seems to go away once I get going.

I know its a lot, any help on any of these would be great, complete novice and learning as I go.

 

[alldodge]

Have a motor serial number?
A new to you boat should always start with baseline maintenance. Need to get it all done so you know what the boat needs or doesn't need

1. Oil in the rear could be many things from valve cover, rear main seal, or other. Need to look up and follow

2. Saying the plugs were dirty, do you mean black from oil and not actual dirt? Take the fuel filter off and dump the contents into a clear container. Your looking for anything other then clean gas. Replace with a new filter

3. Pull the outdrive, change the drive lube, replace the impeller and or pump assembly. Check the bellows, gimbal bearing, U joints and drive alignment. The water can come in from the transom assembly, hose connections or boots. The upper steering pin and Y pipe can also be the issue

4. Some white smoke is not that much of an issue so long as its just a little. Water flows thru with the exhaust. Smelling of fuel may need a carb rebuild or other if EFI

 

[Rick Stephens]

AD speaks wisely. If you are rich, and want to have a marine mechanic do your maintenance, then the time to take it to him was when you bought it, before you break something spendy. And this forum is probably unnecessary to your needs.

If you are like all of us, wanting to DIY and maintain a boat on your own, even maybe sometimes on a budget (lotsa gotcha's there), then this is the right place to be.

Taking care of a boat starts out the day you get it. You must assume none of the maintenance was done by the previous bored with it all owner. So sit down and read the maintenance items in the Merc Service Manuals. www.boatinfo.no for free online versions. You can purchase printed one as well. You will need some tools, special to Mercs, an alignment bar is the very first and necessary one. You just have to get in and make sure the thing isn't going to burn up or sink in the near term. Longer term thinking is the more you know about maintenance items needed to keep running safely, the less likely you are to break expensive parts without need.

Also spend some time reading in the Adults Only section of this forum. There are loads of things you need to know about your boat.

 

[Bluemelj]

Thanks for the quick reply, attached is a picture of one of the spark plugs. I am going the diy as far as I can go, have already replaced both trim solenoids and the starter slave solenoid, very minor I know but was a good first start for me.

plan to change fuel filter this week again thanks for the info!!

 

[Bluemelj]

Forgot to mention cannot find the motor serial number for the life of me? Any help?

 

[Rick Stephens]

Adults only!

https://forums.iboats.com/forum/eng...rcruier-stern-drive-and-engine-serial-numbers

 

[alldodge]

Your burning some oil and with the outside of the plug having oil on it I would look at the valve cover gasket. If the motor has blow-by it could also be belching out on top the cover

 

[pacofortacos]

3. Water in the bilge, when on the water its trickling down from somewhere between the engine and outdrive but cannot find the source, when hooked up to muffs I see a small drip of water from the exhause manifold but nothing compared to the trickle coming down when in the water.

Check where the manifold to riser gasket is for a leak. It's possible you have a leak there or in the manifold or riser and it is spraying back when on the water. On muffs, there isn't as much water flow through the exhaust manifolds as there is when on the water.

 

[Bluemelj]

Not a good day at the lake!!!!

With all my problems I probably shouldn’t be on the lake today but it was the last one for the year, within about 20 minutes engine started missing again and then appeared to seize up. I was not in the boat had to run a quick errand and ended up being towed in.

dont know if it got hit but I do know there is water in the engine. Removed all spark plugs each had droplets of water but one almost gushed out water.

where do I go from here!

thanks....

 

[alldodge]

My first thought is the motor overheated

 

[Bluemelj]

Where do I start looking for the source of water?

 

[Rick Stephens]

What causes a motor to fill up with water? Cracked exhaust manifolds, cracked block, blown head gasket, intake gasket leak.

Probably need to plug the water lines going to the exhaust manifolds and pressure test the block.. Listen for where it leaks to get some idea of what the issue is.

 

[pacofortacos]

Manifolds and risers of unknown age are always top suspects. - Esp. when you have droplets or more leaking out of them to start with.

 

[Bluemelj]

Everyone thanks a bunch for all the replies, had a friend come by yesterday with some boat knowledge and a lot of car knowledge and we did the following.

1. cranked the engine to c how it sounded with no spark plugs and there was no noticeable noise, we did that multiple times to get water out of the cylinders.

2. drained all water out of the engine from drain plugs

3. once we could not c any water coming out of the spark plugs holes from cranking the engine we put plugs back in and tried to start it.

it acted like it wanted to start but did not and back fired once when giving it some gas.

next plan is to replace spark plugs and try to start again assuming that the plugs got wet and are damaged.

is this a good path to go down?

 

[Bluemelj]

So I should have clarified, the path above is to see if the engine will start, I understand I still need to determine why I am getting water.

from comments am I correct in saying that the exhaust system is a possibility and probably best case scenario?

for example, shutter assembly(flapper), exhaust manifold, bellows, what else. As I am understanding my engine I have the single piece exhaust manifold.

i understand there could be a cracked block, or other internal issue. Thanks again for any input...

 

[alldodge]

Are U sure the plug wires are back in correct order?

If old plugs worked before they should work again but nothing wrong with new plugs. Plugs that get wet, once dry should have no issue firing

 

[Bluemelj]

Yes positive that plug wires are back in order, spark plugs were put in the day before the motor took on water so they are new. Was worried that they were damaged from taking on water.

when trying to start getting some occasional smoke from carborator.

 

[Bluemelj]

After letting the boat sit for a week because it was raining, the boat started up first try. Only ran it for about 15 seconds because I did not have it hooked up to water.

then I removed my 1 piece exhaust manifolds and found that the side with the most water had a bad flapper. Can I assume this is the reason I got water in the engine. One piece exhaust manifolds looks visually ok but it seems while I have them off that I should go ahead and replace with 2 piece set, thoughts?

also noticed oil on my valve covers should I replace valve cover gaskets while manifolds are off?

thanks

 

[alldodge]

If valve covers are ;leaking then yes replace gaskets

A bad flapper will not necessarily allow water into the motor. You would have to stop fast or the motor diesel when shutting down

 

[Bluemelj]

alldodge understand on the flapper, other than the exhaust manifold what could it be?

ran the boat for about 10 hours prior with no water issues, don’t you think bigger internal issues would have shown up right away like a cracked block or something else, it’s never ran hot and still do not have water in the oil.

maybe I am being way to optimistic that it is either the flapper or these old one piece exhaust manifolds.

thanks...