Possible engine trouble..... opinions wanted please.

[bluemarshboater]

I started to pump out my oil yesterday to find what seems to possibly be water in the oil. The oil is a bit thin and brownish. I bought the boat without a test drive..... when I looked at the boat and checked the dipstick all looked and smelled fine, as it did right before I started to pump it out. The little bit of oil on the plugs (I know, not good) looks normal. The running of the engine without a load seems fine and I know that really means nothing.

I guess my question is..... is it possible that the oil hadn't been changed for quite some time, broke down and the water could be from condensation?

I'm taking it out Saturday with fresh oil. I'll stop every now and then and check the oil to see if the level rises and/or the color changes.

Best
Dave

 

[snoski]

Re: Possible engine trouble..... opinions wanted please.

How long was the boat sitting before you bought it and eventually cranked it? Are you running the boat with muffs attached to the outdrive? I would change the oil and run it again on the muffs before ever putting the boat in the water... Be sure about your motor before taking it out...

 

[Schmoe]

Re: Possible engine trouble..... opinions wanted please.

Usually you'd find some white color when water mixes with oil. If it's been sitting for awhile, you'd find water at the bottom of the crankcase. Oil on the plugs could indicate bad rings. Might want to run a compression check.

 

[bluemarshboater]

Re: Possible engine trouble..... opinions wanted please.

Thanks for the replies. Yes the boat sat for at least a year from the previous owner who had ran it one time last summer. Don't know how long it sat prior to that.

I will get a compression gauge and check the compression.

My house doesn't have great water pressure, so do you think I should sit the outdrive in a big tub instead, or will the water pump still work even with low pressure?

Best
Dave

 

[bluemarshboater]

Re: Possible engine trouble..... opinions wanted please.

Compression should be around 125?

Best
Dave

 

[mkast]

Re: Possible engine trouble..... opinions wanted please.

125 is a tad low. Engine size?

 

[bluemarshboater]

Re: Possible engine trouble..... opinions wanted please.

I didn't do a test yet, but the engine size is the mercruiser 5.0 with Thunderbolt IV.

 

[Alumarine]

Re: Possible engine trouble..... opinions wanted please.

You should be able to run it on muffs with low pressure.

I never turn my hose on full.

Just make sure water is coming out the exhaust.

 

[bluemarshboater]

Re: Possible engine trouble..... opinions wanted please.

Thanks for the replies.

Looks like the compression should be 140 - 160 with nothing greater than 10% variance between cylinders.

Sound Correct?

 

[Alumarine]

Re: Possible engine trouble..... opinions wanted please.

Ideally yes. I wouldn't rebuild an engine that only had 125 though unless it had other issues.

Thanks for the replies.

Looks like the compression should be 140 - 160 with nothing greater than 10% variance between cylinders.

Sound Correct?

 

[bluemarshboater]

Re: Possible engine trouble..... opinions wanted please.

Since compression checks need to be done to a hot motor I need to change the oil first. I'm having a hard time getting it out via a dipstick tub pump. Just spitting and sputtering, maybe it's not sealed correctly and is sucking air.

Anyone change the oil a different way.... using a pan in the bilge if one fits?

Thanks
Dave

 

[mkast]

Re: Possible engine trouble..... opinions wanted please.

Even if you get a pan under the engine, how are you going to get the pan full of oil out?
Double two garbage bags.

 

[bluemarshboater]

Re: Possible engine trouble..... opinions wanted please.

I thought of that, so would either have to do it a little at a time or pump it from the pan to another container.

I'll give the garbage bag idea some thought. Have you done it that way?

Best
Dave

 

[rbh]

Re: Possible engine trouble..... opinions wanted please.

get as much oil out as possible through the tube, if you are worried about water it can be determined how much by pulling the plug on the pan and using the two bag method to collect, cut hole in corner and drain into glass jar, let sit and you will see the water and oil separate?
rob

 

[bigskiohio]

Re: Possible engine trouble..... opinions wanted please.

i used the two garbage bags works awsome ,i had some water in mine and pulled plug and let it drain all day will never do it any other way . with regular oil was alot faster then the pump. if you have room i reccomend it, the hose out the back i hear is slow and the pump is slow and wont get all of it.

 

[mkast]

Re: Possible engine trouble..... opinions wanted please.

If you know how to place the hose in the dipstick tube, all of the oil comes out.

 

[bluemarshboater]

Re: Possible engine trouble..... opinions wanted please.

Yes it was not making a good seal. Tightened with pliers and whola it all came out.

Best
Dave