1988 Mercury 150..

[Cajunkirk]

Had some trouble with the engine missing real bad at high speeds to the the point of her not taking any throttle. Sounding like she was chokin down. Checked all the cylinders for compression. All of them above 112 but none above 116. Had good spark and the stator and trigger checked good, so I decided to rebuild carbs. Replaced all the parts in the carbs to include new jets. Started her up and now she is shooting oil and gas out near the prop.. A lot of it.. And running a lot rougher at idle.<br /><br /> A few thoughts, floats set too high, jets to large... But not real sure where to go from here. Any ideas... Ole Girl is making me craaazy...<br /><br /> Thanx.. Kirk

 

[Barnacle_Bill]

Re: 1988 Mercury 150..

Definately recheck the floats.

 

[Cajunkirk]

Re: 1988 Mercury 150..

Originally posted by IBNFSHN:<br /> Definately recheck the floats.

Do you think that the oil and gas coming from the prop could be caused by flooding due to the floats being improperly adjusted? Or is it more likely to be a bad reed?

 

[Cajunkirk]

Re: 1988 Mercury 150..

Okay.. Now I am really confused.. Reset all the floats to spec.. The top carb does not have a number on it for me to look up the correct jet size. All it has stamped on it is WH. I still have gas and oil coming out of the prop. Any other ideas?<br /><br /> Oh yeah.. I dont know if this has anything to do with it, but I did check all the timing and carb sync and it is right.

 

[Barnacle_Bill]

Re: 1988 Mercury 150..

Check your bleed lines and check valves where the bleed line connects to the block. Be sure the bleed lines go to the correct carb. Also be sure your choke is opening or your enrichner is operating correctly. If none of this helps and no one else has any ideas, you might try asking at http://forums.screamandfly.com/index.php?s=

 

[Cajunkirk]

Re: 1988 Mercury 150..

Originally posted by IBNFSHN:<br /> Check your bleed lines and check valves where the bleed line connects to the block. Be sure the bleed lines go to the correct carb. Also be sure your choke is opening or your enrichner is operating correctly. If none of this helps and no one else has any ideas, you might try asking at http://forums.screamandfly.com/index.php?s=

Thanks IB. I had not thought about the bleed lines. I will check the condition of them tonight when I get home. I was thinking of just taking all the carbs back off and starting all over again as far as the hoses go. There are some of them that are cracked at least externally.<br /><br /> I went back to the home page of the board and read some of the post on the outboardrepair site. There is some very good info there. I would suggest that to all the new cadets. Seems that there are several possible causes of the fuel leak from the prop. I have printed them out and plan to take the whole day tomorrow without the lil woman and kids around. Sometimes that can be very distracting. Last night I wrote out a step by step checklist that I want to check out starting with the spark and working my way through to the fuel system.<br /><br /> thanks again for the suggestions.... Kirk

 

[LubeDude]

Re: 1988 Mercury 150..

You mentioned that you changed the jets, Why? Did you put the same size back in? Bigger smaller?<br /><br />Curious.

 

[Cajunkirk]

Re: 1988 Mercury 150..

Originally posted by LubeDude:<br /> You mentioned that you changed the jets, Why? Did you put the same size back in? Bigger smaller?<br /><br />Curious.

Should have mentioned this before dude.. I took it to a mech and he tole me that I probably had some jets that needed to be changed in the top carb cause I was not getting no fuel in the top two cylinders. Upon reading the Clymer manual that my Brother gave me, it says that there are no carb adjustments and if you think that you need to run richer, go with a bigger jet. So yes sir. I did go one size up from the original one that was in the carb. One of the things that I had planned on doing tomorrow was to go back through the book and go back to the factory jets. Or at least what the book calls for. I was going to give it the ole Chief try though because the carbs are not listed in the book per-say. They dont have any numbers stamped on the top like the book calls for so I am just going to go with the closest one for that year and serial number.<br /><br /> Do you think that the bigger jets may have something to do with the fuel coming out of the prop? Maybe I am flooding the carbs out?

 

[LubeDude]

Re: 1988 Mercury 150..

I dont think the jets have anything to do with your problem, I would have to say you need new needles and seats on all three carbs.<br /><br />Also, what kind of floats do you have, are they a solid foam, hollow plastic, or brass.

 

[Cajunkirk]

Re: 1988 Mercury 150..

Originally posted by LubeDude:<br /> I dont think the jets have anything to do with your problem, I would have to say you need new needles and seats on all three carbs.<br /><br />Also, what kind of floats do you have, are they a solid foam, hollow plastic, or brass.

I replaced the needles and the seats in the #1 carb but the other two seem to be fine. I am still thinking of just starting from scratch and checking all the hoses from start to finish. I did not have this problem until I rebuilt the carbs and I am thinking that one of two things have happened. One when rebuilding the fuel pump, I put to much pressure to something, or two, I did not connect something right.<br /><br /> All of the floats are the hollow plastic ones. Does that make that big of a difference?

 

[kend414]

Re: 1988 Mercury 150..

I was told that you need a minimum of 120 lbs of compression for the motor to properly operate the reed valves. I was told by the local merc dealer/owner/head mechanic.

 

[Cajunkirk]

Re: 1988 Mercury 150..

Originally posted by kend414:<br /> I was told that you need a minimum of 120 lbs of compression for the motor to properly operate the reed valves. I was told by the local merc dealer/owner/head mechanic.

If I am not mistaken, the manual says as long as you are over 100 with not too much difference between the cylinders, you are okay.<br /><br /> Just for info.. I had taken off all three carbs, checked for bad needles, seats, made sure the floats are set right, and I am still throwing gas out the prop. I am slowing running out of ideas. This morning I took the carbs back off and I am checking all the hoses for leaks or a lot of wear. <br /><br /> I also saw something in the manual about an enrichner valve?? Does anyone know where I can look to find that? I dont have any idea where it would be.