Merc 1985 150 not enough power to get up on plane

[FlashOverX]

1985 Outboard Mercury 150<br />Oil is added to fuel, original buyer oped not to get the oil injection.<br /><br />This started last season usually when engine was not warmed up all the way. I would idle out to the end of the no wake zone. When I went to give it gas it would speed up but could not get onto a plane. In the past I just had to run it at a high speed for a bit and then it was like it decided ok I am ready to go and it would speed up and away I went. Initially I decided to get new spark plugs so I got what the manufacturer suggests and some carb cleaner. I also added some fuel additives that the local dealership recomended. The engine ran better but I still had random problems with lack of power. I checked the fuel screen which it was clear, removed the carbs which are in good condition. Spark plugs do have some oil on them when I took a look at them(Black oily residue). Now I checked the timing and adjusted the primary and advanced to 14degree and 18 degrees. I ran some tests while on the water today. In neutral the engine revs up just fine and seems to have plenty of power. THen when I put it in gear it seems to never get out of first gear so to speak. <br /><br />I am pretty sure its not electrical so I think I need to start trouble shooting fuel issues. <br /><br />One other note this has gradually been getting worse and now I dont get on a plane at all. I have used 2 sets up plugs so I know they are good. I also used the old plugs when I applied the carb cleaner and put in the new ones after engine sat and was reran after the waiting period.

 

[Kiekhaeferscurse]

Re: Merc 1985 150 not enough power to get up on plane

Hello FashOverX, Do you have a tach in the boat? You say it will eventually get up & go when it does get up on plane what are the wot rpm's, when its struggling to get up on plane what are the rpms at?<br />Just a shot in the dark but it sounds like your not hitting on all 6 cylinders, possible running on 3 then the others kicking in (bad pack) or running on 4 then 2 more kick in(trigger) or running on 5 and a coil kicking in. If you have a DVA this will be an easy trouble shoot. or a good set of plug pliers (insert Big grin here)<br />If possible supply the techys here with a little more boat info, type of boat, prop, did the engine run good then you layed it away for winter..etc etc<br />Good luck Cheers

 

[down_time_1]

Re: Merc 1985 150 not enough power to get up on plane

FlashOverX,<br /> Have you checked your fuel pump? I had a 135 v6 searay and had a problem like yours and had to rebuild it at a dock on the water at Norris Lake in tenn . (cost about $10.00 in parts) Hope this helps

 

[FlashOverX]

Re: Merc 1985 150 not enough power to get up on plane

Well right now I have to work on rewiring most of my console. Due to corrosion none of my instruments work, just replaced the fuse block and hopefully will get everything rewired.<br /><br />Some possible helpul info:<br />Procraft BassBoat<br />17ft I believe<br />I have spent numerous hours in the winter doing preventative maintenance like changing out the water pump, oiling and greasing, new starter brushes, etc. I also change the lower unti oil twice a year or more if needed. I am not sure of the prop size/pitch stainless steel but I can tell you it worked perfect for the first 2 years I had the boat. I am also in Kentucky where our winters are rather mild and the boat is garage kept. I usually get the boat out 10-15 times through the winter and drain the prop and store back in an insulated garage.<br /><br />I do have a manual that I use for my repairs Clymer's Official Shop Manual.<br /><br />For that past 2 years this problem has gotten progressively worse. However it was not all the time and this was the first year that after warming the engine up that it would continue to do it.<br /><br />What is a DVA? This is my first boat and I try to take very good care of it but also do the work on it myself so I can understand issues it might have.

 

[FlashOverX]

Re: Merc 1985 150 not enough power to get up on plane

Fuel pump is what I was going to take a look at next. From reading some of the other problems people have had I thought it would be a good bet. Compression is still a possibility but the fact that I can put it in neutral and it revs up just fine makes me wonder what the problem could be. I have also read that I should update the floats in the carbarateur but I will hold off on that. Just needed to get some ideas what to test this week while the weather is warm.

 

[phatmanmike]

Re: Merc 1985 150 not enough power to get up on plane

Compression is still a possibility but the fact that I can put it in neutral and it revs up just fine makes me wonder what the problem could be.

this mean snothing. all this means is that when your engine is under a load, it works as it should.<br /><br />i had an evinrude 50 that ran GREAT out of the water, or in nuetral, but once in gear, it was only running on 1 cylinder,so it was dropping a cylinder under load. <br /><br />if this is your problem, which it just may be, you have lost of items to look at.<br /><br />if your fuel pump is bad, its gonns usually be bad all the time, not just when its under load.<br /><br />you really need to check the compresiion numbers.without knowing this, its all just a guessing game.<br /><br />have you checked your spark while under load with a spark tester ? perhaps your spark isnt strong enough to spark under compression at high engine speeds.<br /><br />you could just simply have dirty carbs. the jets in there are REALLY REALLY small and could be clogged with just enough goo, to screw things up.<br /><br />also, dont rev your outboard in nuetral. thats certain death right there.

 

[Kiekhaeferscurse]

Re: Merc 1985 150 not enough power to get up on plane

DVA= Direct Voltage Adaptor <br />Its like a multi-meter but it allows you to check the voltage at the coils among other places when the engine is running, its an easy way to check if all 6 coils are getting there alloted 200 volts. Just trying to determine whether or not the engine is actually running on all 6 cylinders, Like the phantom says if it revs up in neutral it really doenst mean anything.<br />Did you have tach in the boat?<br />P.S. You can purchase a DVA from any merc dealer p.n 91-99750 its a great tool for that big V6 and it comes with a great trouble shooting chart (no i'm not a Merc dealer on a sales pitch) it will pay for itself many times over though and if you plan on keeping that engine by one.<br />Good luck & Cheers

 

[FlashOverX]

Re: Merc 1985 150 not enough power to get up on plane

Thanks for all the great suggestions! I am really glad I found these forums. I have heard to many horror stories about local mechanics doing more damage and needless repairs in this area. So finding a place where I can get helpful tips is greatly appreciated.<br /><br />Kiekhaeferscurse: I plan on getting a Merc for my new boat in the next 2 years so it sounds like the DVA will be a good choice. I am searching the net right now for a compression tester then I will run up and get a DVA later this week if I can. Will post my results when I get them.<br /><br />Thanks Again<br /><br />and no I dont have a tach on the boat at this time.

 

[Lakelad]

Re: Merc 1985 150 not enough power to get up on plane

I know this sounds crazy but have you checked for a spun out prop. If so your RPMs will go up but your boat will not go.

 

[shipoffools]

Re: Merc 1985 150 not enough power to get up on plane

Don't ignore the fuel pump. It's way to cheap and easy not to rebuild while your doing everything else suggested. My 70 hp had me tearing what is left of my hair out last summer and finally after countless plugs carbs off 3 times for cleaning, coil testing, stator and switch box testing etc. etc. etc. a $10 kit and 15mins and the motor ran like new.

 

[KCLOST]

Re: Merc 1985 150 not enough power to get up on plane

phatman is giving you the best and easiest advice to start out with...<br /><br />Check the spark on all the cylinders and the compression.... <br /><br />For spark, I'd use a spark gap tester, $10. This will measure the intensity of the spark(s) or lack thereof. If you are losing fire in only one cylinder, your rig will have a hard time getting up on plane, trust me I know from experience.<br />Second you must check compression also. Easy to do with a compression guage from any auto parts store. <br /><br />Eliminate those as a possible cause first, only $30 to spend if you don't have the testers already and valuable stuff to have around in the future. <br />If you are ok with the spark and compression, then the fuel (lack of it) is most likely the culprit. <br /><br />Let us know...

 

[KCLOST]

Re: Merc 1985 150 not enough power to get up on plane

Any news?

 

[heybaylor]

Re: Merc 1985 150 not enough power to get up on plane

I have a 86 150 , and had the same problem/ problems.<br />After changing fuel/pump rejetting carbs , and plugs , on, and on ..<br />what my fix was ,,,the ignition control box was the culprit ..it is supposed to "stabilze the low rpm,s ..and retard the spark a little at high rpms..<br />wel it stabilizes , by advancing , and/or retarding the timing at low rpm,s..<br />mine was jumping all over the place ...severe retard to wild advanced<br />disconnect the "white wire" on it ..see if your problem goes away ..<br />then replace the box ..I fought this for about three years ..now my 86 150 merc is smooth everywhere ,,,( I still have it)..<br />the white wire is the "spark control wire "<br />unhooked, it is out of the picture ..<br />do replace the box even if it runs good , because the idle is better with it , and you will not have the "retard" at rpm over 5800 without it .<br />hope this helps

 

[hookset56]

Re: Merc 1985 150 not enough power to get up on plane

Heybaylor,<br />I also have a 1985 150 with the same problem.<br />I looked in my Merc service for the ignition control box and cannot find a part with that name. I did find a low idle control and a high/low idle control box. Their functions are as you described, are these the same as the ignition control box?

 

[KCLOST]

Re: Merc 1985 150 not enough power to get up on plane

You're looking for the switchbox hookset!

 

[hillclimber61]

Re: Merc 1985 150 not enough power to get up on plane

Originally posted by FlashOverX:<br /> 1985 Outboard Mercury 150<br />Oil is added to fuel, original buyer oped not to get the oil injection.<br /><br />This started last season usually when engine was not warmed up all the way. I would idle out to the end of the no wake zone. When I went to give it gas it would speed up but could not get onto a plane. In the past I just had to run it at a high speed for a bit and then it was like it decided ok I am ready to go and it would speed up and away I went. Initially I decided to get new spark plugs so I got what the manufacturer suggests and some carb cleaner. I also added some fuel additives that the local dealership recomended. The engine ran better but I still had random problems with lack of power. I checked the fuel screen which it was clear, removed the carbs which are in good condition. Spark plugs do have some oil on them when I took a look at them(Black oily residue). Now I checked the timing and adjusted the primary and advanced to 14degree and 18 degrees. I ran some tests while on the water today. In neutral the engine revs up just fine and seems to have plenty of power. THen when I put it in gear it seems to never get out of first gear so to speak. <br /><br />I am pretty sure its not electrical so I think I need to start trouble shooting fuel issues. <br /><br />One other note this has gradually been getting worse and now I dont get on a plane at all. I have used 2 sets up plugs so I know they are good. I also used the old plugs when I applied the carb cleaner and put in the new ones after engine sat and was reran after the waiting period.

I have the same problem. I have a 1984 mercury black max 150 6455415. Its on a ranger 370 bass boat. My motor Starts and idles but when asked to go it only goes to 2000 rpms. It does that for a while then gradually the rpms go to 3000. Still not enough power to get out on plane. After a while more it gets to 4000 and quickly I get on plane and 5000 rpms comes quickly. This happens my 1st time out of the hole each fishing trip. This takes about 5 minutes each time I go out. After the boat planes out and I run, It does not happen again that day. Getting the boat on plane the rest of that day takes a few seconds more than it used to (5 seconds) still a bit sluggish.<br />This boat used to jump out of the hole<br />Can any one help<br />thanks Fred

 

[KCLOST]

Re: Merc 1985 150 not enough power to get up on plane

semi,<br /><br />The first and easiest thing to check is the spark on all the cylinders.... <br /><br />Run the engine on the muffs at idle... Use a spark gap tester which you can buy at any auto parts store for around $10....Set the tester on one lead to the plug at a time before starting the motor. And set the gap at 1/4"-3/8" for starters... The gap tester allows you to test each lead and still have it grounded to the plug.. If the spark is strong enough it will jump the gap and you can see it easily without shocking the hell out of yourself by doing this the old fasioned way...<br /><br />Switchboxes have been known to go in and out of operation with changes in temperature... So this may be the cause of your problem... So checking the spark at cold/idle conditions is my best recommendation...And I should add, that a weak spark can also cause your problem at lower rpms...<br />A weak spark can be related to something besides the switchbox, but we will get to that later. Let us know what spark intensities you have on each.<br /><br />If you have only one cylinder not firing, it's very possible the boat will not get on plane... I have a Ranger 371V that "barely" got on plane with only one cylinder not firing... <br />If we check the spark first we will know if it's electrical or not, if the firing is ok, we will then need to check compression and fuel...<br /><br />Fuel/air+compression+spark=combustion<br /><br />Without one of the three you will not go, so lets start with spark first...

 

[Roger Urwin]

Re: Merc 1985 150 not enough power to get up on plane

I have a similar problem to FlashOverX with a 1990 200hp mariner, but mine has the bonus problem of running out of fuel sometimes when idling, pumping the primer bulb fixes it.This may be part of the problem or something completely different. My main problem is as FlashOverX describes, which seems to be getting worse,now unable to get revs above 4800 rpm, & running too hot, (water pump has been replaced). I've changed the plugs,had the leads checked, rekitted the fuel pump,checked compressions, no better.Any suggestions would be welcome.

 

[KCLOST]

Re: Merc 1985 150 not enough power to get up on plane

Assuming your tank is venting properly and your tank and inline fuel filters are clear, which can also cause your symptoms..<br /><br />My bet is you're running lean by a gummed up carb... Meaning Lean on fuel/oil to air... This will cause overheat and basically starve the engine leading to loss of power also...<br /><br />Time to clean the carbs thoroughly, but check the filters/tank venting first......

 

[lmoreau]

Re: Merc 1985 150 not enough power to get up on plane

I kind of have the same problem...sometimes the thing will hit full rpms when you stomp on it, sometimes it will hesitate, then speed up. It sounds like it's bogging down.. I may also have a miss at around 3000-3500 rpm. Seems like it anyway...1989 150.