Merc 150 hp problems

[gsmith145]

First off i bought this boat a few weeks ago 1985 monark mcfast 172 with a 1985 150 hp mercury serisl #6009545 V6 he told me that it ran great no problems he put stabil in the gas before he put it up last winter and has not ran it since. I have taken it out 5 times now and cant get it to run right.It wont idle well and it wont accelerate at all. trouble shooting i have foud the following:<br /><br /> an intermittent spark in the 1 cyclinder sometimes its fine and somtimes it just wont spark at all. the motor will only Idle with the motor about half way up in trim. I can turn the enrichment valve about 2 tuns clockwise and the motor picks up and runs well. Gained about 15-20 mph. I have poor fuel consumption. my trigger and stator test good also. after i get back home and put it on the muffs it wont run unless i adjust the enrichment valve.

 

[gsmith145]

Re: Merc 150 hp problems

also I have elimnated a bad coil and swithed stator leads on the switch boxes and it stayed with the swith box. is that problem cause some one told me that if i adjust the enrichment valve and it runs then its a fuel problem. Could the extra fuel not being burnt cause it to foul out the plugs or run rich. This motor has no oil injection. its been removed and I premix 50:1. I noticed a lot of gas being sprayed back into the sound box is this normal. Thank you

 

[KCLOST]

Re: Merc 150 hp problems

Ok, this looks like a switchbox problem... One way to check for sure is to "switch" both switchboxes.. Make sure you keep track of all the wires so they go back in the proper place.<br /><br />If the no spark condition moves to another cylinder which will be on the other side of the motor you have a bad switchbox... And in that case you need to replace both of them with new CDI/Rapair units...<br /><br />Now on the fuel related issue, it is very possible that you just have gummed up carbs that need a good cleaning by taking them apart, following the manual and making sure any gummed up crap is in there...<br /><br />You could have both problems, but start with the switchboxes first, it's eaisier imho...

 

[gsmith145]

Re: Merc 150 hp problems

I have cleaned all three and still the same thing is it possible for the unused gas to be flooding the engine

 

[gsmith145]

Re: Merc 150 hp problems

Why do I need to replace both of them?

 

[DOCD9501]

Re: Merc 150 hp problems

It is always suggested to switch both because in most cases they were put on together and have the same life cycle. Trust me when I say you dont want to undo all those wires more than once. When one goes bad the other usually follows shortly there after.

 

[DOCD9501]

Re: Merc 150 hp problems

Oh sorry I forgot. I dont know about KLOST but I dont ever suggest using the enricher to help solve a problem. If you are picking up when turning it up, that somewhat states a lean problem which is asking for disaster. Clean up those carbs too. Lean is mean but can cause a bad dream!

 

[gsmith145]

Re: Merc 150 hp problems

which way does the enrichment valve need to be set right now it all the way up(counter clockwise) I have cleanded up the carbs but too no resolve. the other switch box looks new. no corrsion on terminals and is the new # can i get away with replacing just the one. What can make a motor run lean

 

[DOCD9501]

Re: Merc 150 hp problems

You can try one switch box if the other is new. As for the enricher I am looking that up. I will get back with you because I am not for sure. Lean is caused by too much air mixing with the fuel which ='s lack of fuel which = not enough lube = boom. Make sure your floats aren't too high. They should be adjusted to level with the carb when the bowl is off and holding it right side up. If they are too high it won't allow enough fuel into the bowl and the jets will empty the bowl faster than they fill up. But if you get them too low it will allow too much fuel which will cause flooding. Ill check that valve for ya.

 

[KCLOST]

Re: Merc 150 hp problems

gs, If you have one switchbox that is new, you may be ok with just replacing the bad one if it is an old one.<br /><br />But, have you switched them yet?

 

[gsmith145]

Re: Merc 150 hp problems

I have switched the stator leads going to the boxes but i havent actually swithed the boxes should I? the problem still stayed at the same box when I switched them. Is it normal for it to spark well for a day then start missing a few sparks every seconds

 

[gsmith145]

Re: Merc 150 hp problems

thank you guys for all your help i really just want to go fishing but dont want to tear up the motor

 

[gsmith145]

Re: Merc 150 hp problems

found a used box off a newer motor gonna giove it a try hope it works

 

[KCLOST]

Re: Merc 150 hp problems

It's not uncommon for that to happen....<br /><br />It's the beginning of the end for a switchbox...<br />Try the other box you got ahold of and give it a try... <br /><br />But I would like you to fully confirm that one of your boxes is actually bad.. You are on the right track by swithing the stator leads, that makes sure that the stator is ok, but not necessarily the trigger. There may be a problem there.<br />Just trying to save you from spending money before you know the exact cause. <br /><br />However it does sound like a failing switchbox..<br /><br />Let us know...

 

[gsmith145]

Re: Merc 150 hp problems

I have tested restince on all the trigger leads and they are in spec with the book........<br /><br /> I just wish i could figure out my acceleration problem, sometimes it takes me a minute or two to get to plane and then only 30 mph. Then for know reason the motor will open up and then back down very slowly this pattern will accure all day long. Even when the box is firing right. I turn the enrichment valve clockwise and poof its gone. runs like new..<br /><br /> What does turning that valve do and where should it be set.

 

[gsmith145]

Re: Merc 150 hp problems

Guys just found out that I have been flooding the motor with the valve all the way open. Guess there are no problems with the fuel. closed it up and vroom it went like it should thank you to all who helped me

 

[gss036]

Re: Merc 150 hp problems

That is a good question for the mechanics? Does the enrichment valve bypass the carbs? But as a rule, you have to activate it for it to work, it should not be pumping gas w/o the little button on top being pushed in or the key being pushed in when starting.

 

[gsmith145]

Re: Merc 150 hp problems

Gary<br /><br /> my fev has an adjustment on top in which i was able to open so i could manually choke it.... <br /><br /> When i bought the boat the valve was open, my thinking the guy didnt want to clean the carbs.. after i cleaned the carbs it started to flood the motor so i had to close it by turning it clockwise.. Does this sound correct