2004 Mercury 150 xr6

**rickriddle** · 07-29-2015, 02:57 PM

Have you guys had any problems with the o-ring heads leaking? I keep getting what I believe is water intrusion into this motor after rebuild. Changed the base gasket and still have the same issue. Carbs get a white frothy stuff in the throats that looks like water and oil mixing. Think of going to an old style head with gasket to see if that fixes the problem. Any ideas on this issue or has anyone dealt with this problem?

**CircleHook** · 07-29-2015, 03:48 PM

Better check your gas- with clear bottle - oil tank too if you are using one.
I am pretty sure stuff flows in the front of the engine and the back so not sure how water in the cylinders would get to the carbs- same applies for base gasket
I don't think the gasket idea is going to work on O-ring heads- but I don't think that where your problem is.

**TEXAS20225** · 07-29-2015, 04:26 PM

water can get into motor via heads leaking ,exhaust divider leaking, i popped a 225 pmax once like that, it will show up on plugs they will be clean as a whistle and it will high high compression in bottom two holes , it can also get in there via a crack in the block but i would check my fuel tank contents first before i started down that other road its a long one,as for changing over to gaskets you will have to change heads and find out which one to put on because the oring blocks are .044 thousandths taller then gasket blocks

**rickriddle** · 07-30-2015, 04:53 PM

I changed the heads to the old style with gaskets no change. Installing gasket and different exhuast divider plate tomorrow. Starting to wonder if the block does have a crack somewhere. I noticed to day that it hits a wall at 4000 rpms. How close are the holes where the stator bolts down? Could I be off a hole causing the problem? Reason I ask is I have base timing retarded completely and the motor still idles. Most motors I've worked on will die if you have them fully retarded. Going to look back under flywheel tomorrow. Never ran into this before. If the divider plate is the problem it would have to have a bad leak. My gut still tells me I'm getting water in some how.

**rickriddle** · 07-30-2015, 04:55 PM

Don't understand the white froth in the carb mouths.

**TEXAS20225** · 07-30-2015, 06:38 PM

40 amp charging systems will only fit in the slot thats allowed by the top cap it cant be off a hole it wont be down on the cap it would be jacked up the thickness of the small piece that keeps you lined up, the froth sounds like something your generating like exhaust cavity has the crack and it getting sucked back through carbs maybe reed is done maybe mota is too

**rickriddle** · 07-30-2015, 08:59 PM

Yeah I put this thing together about a month ago didn't notice a crack anywhere. Had to have on cylinder sleeved but it wasn't that bad so I'm not sure. Never had one do this before. You would think a crack would have been noticeable when it was apart. Rod and piston stayed together rings were toast and cylinder had deep scaring so I had it sleeved. Not sure how it could have crack or where. This thing sounds good when its on the hose very responsive. It will get up on plane and run but goes to about 4000 rpms and seems like its not pulling and more but motor sounds fine . could the exhaust plate have a crack that would be causing this? Also if I pull the exhaust plate shouldn't there be the same milky substance inside it if its cracked somewhere?

**rickriddle** · 07-30-2015, 09:04 PM

When I replaced the power head gasket I noticed the same froth looking stuff around where the drive shaft comes up through the midsection before it enters the bottom of the power head. Could the adapter plate cause this if it was damaged some how?

**rickriddle** · 07-30-2015, 09:16 PM

Why would this thing idle so smooth with the idle timing retarded so bad. The idle adjust bolt is screwed all the way in with nut against its head and it idles fine. Most of the time if you go more than 3/4 of the way in these Mercury's will die. If I add any timing it starts to idle to fast. Idles out of no wake fine no misses. Go to put it up on plane and it stumbles under load then get up on plane but just feels like the power is not there. Goes to 4000 rpms and that's all she has. Could the froth be air mixing with the fuel instead of water? When I watched it with the air cover off the carbs it almost looked like the froth was come out of the carb. I pulled the low pressure fuel pump and it looked fine. This thing is driving me crazy.

**TEXAS20225** · 07-30-2015, 11:06 PM

yes divider can be cracked or even warped , i had one i had to scrap because it kept pumping water into cylinder no matter what i did , the bottom cap is a seal gone i just had to lift my powerhead on one of my promaxs to reseal one it was leaking so bad it was leaving a trail of gas/oil behind the boat when i lifted it up the cavity your talking about on mine was full of the mystery white stuff , i don't know whats up with your timing something taint right for sure, when you say idle bolt do you mean low speed timing screw. did you do the 462 on timing indicator and link and sink ok, are you getting any at all compression out of the carb throat? also who put the sleeve in? it could be toasted between the sleeve holder and sleeve!!! water can come in between them believe me i know this from experience, if sleeve holder was out of round say 5/6 thousandths sleeve will not touch holder

**rickriddle** · 07-31-2015, 07:05 AM

Local machinist put sleeve in. He does a lot of these and has done several for me without issue. Guess I'll change exhaust divider next and see what happens.

**rickriddle** · 07-31-2015, 07:06 AM

Yes low speed timing screw is screwed all the way in..

**rickriddle** · 08-11-2015, 09:18 PM

Got it fixed stator must have been off by one hole when I put it back on. Timing was the culprit she screams now that it's adjusted correctly. I must have not been paying attention .