re; Heavy oil residue in exhaust

[shadowrider]

OK, it's been awhile since I posted about heavy grease or residue in jet unit exhaust. I was convinced it was bearing grease. I just now got around to doing something about it. I pulled the jet unit and can see heavt residue all the way up the exhaust tube to bottom of block. Motor runs well, has 140 psi onall cylinders and has spark on all 4 cyls. Could this be a timing issue or something else ? I would really like to get this figured out. Hope you can help. Thanks, this forum rocks!

 

[Lone Duck]

Re: re; Heavy oil residue in exhaust

If it is a 2 cycle , the only way you can get that kind of residue inside your exhaust is to rich and oil mix. If it is on the outside, to much bearing grease. If it is a 4 cycle, you have a oil gasket leak. What do your plugs look like ?

 

[shadowrider]

Re: re; Heavy oil residue in exhaust

It is a 73' 85 mer 4 cyl. does smell rich, 3 out of 4 plugs fouled. Were not fouled at last comp. check not long ago. What can cause rich conditions suddenly?
50:1 mix. Thanks for fast response.

 

[Lone Duck]

Re: re; Heavy oil residue in exhaust

Only reasons I can think of is that either you made a error mixing fuel. I once added oil twice. Or your timing has changed. Or your choke is stuck at 1/2 way making it run rich.

 

[shadowrider]

Re: re; Heavy oil residue in exhaust

I did notice an old residue not real heavy prior to this. I verified choke not sticking mechanicaly. I dont think it is my gas mix. My manual is MIA. I will need to find it to check timing. both carbs are set 1 1/4 turn out from seat. Can I check timing with timing light on #1 cylinder. Sticker says 27 BDC. Again, thanks for your input.

 

[Lone Duck]

Re: re; Heavy oil residue in exhaust

Yup! You can use the timing light on # 1 Perhaps a expert firmiliar with that engine and it quirks will chime in soon and give us a hand.

 

[shadowrider]

Re: re; Heavy oil residue in exhaust

I feel like I opened up a can of worms here. I checked the timing and followed the manual except the part where it says to start engine and let it run out of fuel after pulling hose. Timing is around 6-7 degrees btdc at lowest throttle setting and I can not get any lower. book says 3-5 degrees. Could warming the engine make the difference? It is a jet unit without a flush port, so warming it up would require a trip to the river.

 

[Lone Duck]

Re: re; Heavy oil residue in exhaust

I have a 82 merc I L 6 90 hp. My jet foot is the same as yours. No flush port. I think the thing to do is to do a link and sync. You may have to buy a dial gauge that screws into your plug hole on #1. and follow the OMC manual to the letter. After you think you have it all done then take it to the river and put the light on it. Keep doing it till you are satisfied you have it right. Also in your manual is a table that tells you the proper jet size for your elevation, check that out also. remember to pull all your plugs while doing lynk and sync.

 

[shadowrider]

Re: re; Heavy oil residue in exhaust

I was trying to do the link and sync, but I could not get the timing to come in to 5 deg. even when I rotated the dissy by hand. I had all plugs out and grounded, verified tdc with dial indicator. It appeas as though mechanically it wont go. If I force it by hand the spring is compressed and it will go back when released.

 

[achris]

Re: re; Heavy oil residue in exhaust

On the original problem, have you changed brand of oil recently?

Chris.......

 

[shadowrider]

Re: re; Heavy oil residue in exhaust

Truth is, this was a recent purchase for me and have not actually taken it out on the water, only dipped in river to test motor, but never left trailer. I used premixed gas tank from my other boat. I am not a religous user of any brand of oil.

 

[achris]

Re: re; Heavy oil residue in exhaust

Truth is, this was a recent purchase for me and have not actually taken it out on the water, only dipped in river to test motor, but never left trailer. I used premixed gas tank from my other boat. I am not a religous user of any brand of oil.

That may be the answer. Some brands burn cleaner than others... I suspect you got a dose of 'non clean burning' oil and now you have the residue dripping down from the exhaust chamber.

Change to a better brand of oil and your problem should disappear.... along with the oil spots on the driveway.

Remember Occam's razor.

Chris.......

 

[shadowrider]

Re: re; Heavy oil residue in exhaust

Good thought, The timing issue is still buggin me though.

 

[shadowrider]

Re: re; Heavy oil residue in exhaust

What do you think about trying 100:1 synthetic?

 

[achris]

Re: re; Heavy oil residue in exhaust

What do you think about trying 100:1 synthetic?

Johnrude tried 100:1 in the mid 80s with their smaller engines. They are back to 50:1... 100:1 is ok when the engine's running, but doesn't leave enough oil on the internal parts to protect them when the engine is stored....

Chris.........

 

[izoomie]

Re: re; Heavy oil residue in exhaust

My current 1988 90hp johnson had thick oily goop coming out of the prop exhaust when I ran it in the driveway. Only low speed. I thought there was a problem but it ran good on the water and I haven't seen it since.

I think the seller was running it with muffs for potential buyers and it never got hot. Once I ran it at speed it seemed to clean up and never had a problem since.

 

[shadowrider]

Re: re; Heavy oil residue in exhaust

I'l stick with 50;1, Thanks for your replies. Still wondering about the timing issue I stated previously. Cant seem to get proper timing reading no matter what I do. Need to get it before completing link and sync.

 

[Lone Duck]

Re: re; Heavy oil residue in exhaust

I was trying to do the link and sync, but I could not get the timing to come in to 5 deg. even when I rotated the dissy by hand. I had all plugs out and grounded, verified tdc with dial indicator. It appeas as though mechanically it wont go. If I force it by hand the spring is compressed and it will go back when released.

Is it possible that the distributer is 1 tooth out of time ? Maybe the belt slipped ?

 

[shadowrider]

Re: re; Heavy oil residue in exhaust

I checked that, it is in perfect alignment with tdc. (I was hoping that was the case)

 

[Lone Duck]

Re: re; Heavy oil residue in exhaust

I checked that, it is in perfect alignment with tdc. (I was hoping that was the case)

Check the keyway or spline on both pulleys . ( Just fishing now )