150 MERCURY

[J BLANK]

I HAVE A 150 MERCURY (1988). RECENTLY I BEGAN TO HAVE A PROBLEM PLAINING OUT ( LOW POWER ) AFTER CHECKING THE COMPRESSION ON THE CYLINDERS I FOUND #4 HAD ONLY 30# ON IT AND THE REST HAD ANYWHERE FROM 98 TO 105. THIS MOTOR WAS COMPLETLY REBUILD 5 YEARS AGO FROM TOP TO BOTTOM AND THIS IS THE FIRST PROBLEM I HAVE HAD. DO I HAVE A HOLE IN THE PISTON OR CYLINDER WALL OR IS THE RINGS STUCK?

 

[KCLOST]

Re: 150 MERCURY

Well,<br /><br />I would proceed to pulling off the head and taking a look. But first try a thorough decarb of the motor with sea foam through the carbs first and then a heavy dose in each cylinder.. And then re-test... <br /><br />It could be any of the problems you mentioned and a few others....A diry carb could have caused this (you have six of them btw, three sets of two). Are you still running off of the oil pump? If so, I would just run pre-mix from now on.

 

[J BLANK]

Re: 150 MERCURY

i really appreciate your help. i will proceed with your suggestions, but when this problem started and it being fishing season i just remived this motor and put on a Marina 115 hp to run until i can get the mercury 150 repaired. The 115 has been setting up for about a year but i sprayed all the carb's and cylinders before cranking and it idoled fine but when put in the water it won't plain out so i'm sure the carb's need cleaning. i now have them off to been cleaned and rebuild.It would idol fine but would try to stall when put into gear and sfter in gear it wopuld not open up. Dosen't this sound like dorty carb's?<br /> thanks again,<br /> Jim

 

[studlymandingo]

Re: 150 MERCURY

Wow, that is very low on the #4. The rest seem a bit low to me as well. Definitely do the decarb, and be sure to spray some Deep Creep heavily into each cylinder, I would let it sit overnight before firing back up. If a ring is stuck, that could let it loose. Otherwise, sounds like time to pull it apart. 5 years, I would think you should be good to go for a long time.

 

[J BLANK]

Re: 150 MERCURY

Has anyone heard of Carb-medic cleaner, i've been told it is very good but hard to find.I have rebuild carb's before but using other cleaners. Does anyone have any suggestions for the best cleaner to use when rebuilding 2 stroke carb's.

 

[J BLANK]

Re: 150 MERCURY

i took the head off and found that #4 cylinder had a hole in the piston and the cylinder and the head was also very pitted. i put this one on the back burner and have put a 1988 115 mariner on there after rebuilding the carb's and now it won't plane out checked compression and it ilods fine but won't plane out. any suggestions?

jim

 

[tashasdaddy]

Re: 150 MERCURY

after rebuilding the carbs did you do a linc and sinc. this puts the electrical timing in sinc with the carbs. i suggest you start a new post as this is a different motor with a different problem.

 

[timmathis]

Re: 150 MERCURY

Yes. This one is history.