1985 merc tower of power hard to start

[quantumman29]

my engine starts fine in the morning,after I make a long run it is hard to start again,and I always need to prime the bulb when I want to start it,
when the engine does start again,it dies when throttles up,it dosent rev up in neutral and I need to wait for about 5-10 mins of idling before it will rev up and go on plane,

there is always a bad gas smell,and the carbureators are all dripping gas when the engine is not running,
the engine runs great once it gets going again,hits wot at 5800 rpm,then it just begins to loose power like a fuel shortage, when i slow down it stalls and smells like gas.

it will start up again but wont rev up past 3000 rpms,if i wait an hour,the engine starts right up,runs great at wot for as long as i need to go,then it all happens again,

the engine never starts without needing the primer bulb primed,and it never runs great 2 times in a row.

does this sound like gummed up carbs?
also is it normal for water to be running along the spark plugs while its idling?
thanx,
mike

 

[turbinedoctor]

Re: 1985 merc tower of power hard to start

Yes Mike it sounds as if you need to rebuild and clean your carbs and maybe your fuel pump also. Mine likes a lot of fuel to start when cold but when it is warm I just touch the key and it fires right up.

The water running along your spark plugs is probably from a leaking cover gasket. If your motor is a fresh water motor then you may be able to get all the bolts out with out breaking one, if it is a old salty then you may want to take into account removing broken bolts when removing the cover. It depends on how bad it is leaking and how much it bothers you that it is leaking as to whether or not you want to replace the gasket.

 

[ClassyGlassy]

Re: 1985 merc tower of power hard to start

Sounds to me like a leaky/faulty fuel pump and primer bulb. I would do some maintenance and replace all fuel line, connectors, primer bulb, and rebuild your fuel pump.

Excessive over-priming/pumping of your primer bulb will cause your carbs to shoot fuel out of the bowls causing the strong fuel smell and "leaky carbs". Take this in account to what you think is a problem.

Which Tower do you have?

 

[quantumman29]

Re: 1985 merc tower of power hard to start

its an 1985 115 tower
the engine runs great,its just hard to start after the first run of the day,
after it does start its sluggish and wont rev up until all the gas smell is gone,it seems to be flooding or somthing or an air leak,or vacuum leak,i dont want to screw the engine up and i dont want to drop the boat off at some jerkoff who thinks he knows about the engine,

maybe the carbs are gummed up?
i didnt replace the primer bulb but i replaced all lines from gas tank to primer bulb,

 

[arsenalpsu]

Re: 1985 merc tower of power hard to start

The towers are usually hard to start cold and easy to start warm. You seem to be the opposite which is strange. It's normal for these engines to spit some gas out of the carbs when you first start them, but not after you've been running a wile. For safe measure i'd rebuild the fuel pump and carbs BUT i don't think that's your problem or she wouldn't run right for long to start with.....pull your spark plugs and look for any water or rust on the plugs. It seems to me you're not getting any production from one or two cylinders after you run for a bit. Here a guess...in the morning she start up cold all cylinders fire, when she's warm your exhaust seals start to expand and expose a leak/crack/etc letting water in a cylinder or two which does not let them fire...so all that extra gas that is not burning comes out the exhaust and smells like gas.

IF this is correct you should see a piston & spark plug or two that is very clean compared to the others. Take a look and report back. IF this is the case you need to replace your exhaust cover gaskets.....

 

[quantumman29]

Re: 1985 merc tower of power hard to start

I just replaced the plugs last sunday,the bottom plug was the cleanest one,the others had black coal like particles on them,
I ran the boat to prefish a torny wednesday,it started up,made a long run,started again it would start but it wouldnt rev up in neutral and it wouldnt rev up in gear,after a few mins of idling in neutral it would then rev up and go,but after a run of 10 mins or so she would start loosing power like it wasnt getting fuel and it wouldnt hit the rpms or rev up ,it would stall if i let off on the throttle.

and ALWAYS i need to prime the bulb,after i shut the engine down the bulb goes soft within minutes,im thinking its an air leak somewhere.
thats why the strong gas smell always
mike

 

[arsenalpsu]

Re: 1985 merc tower of power hard to start

I just replaced the plugs last Sunday, the bottom plug was the cleanest one,the others had black coal like particles on them,
I ran the boat to prefish a torny wednesday,it started up,made a long run,started again it would start but it wouldnt rev up in neutral and it wouldnt rev up in gear,after a few mins of idling in neutral it would then rev up and go,but after a run of 10 mins or so she would start loosing power like it wasnt getting fuel and it wouldnt hit the rpms or rev up ,it would stall if i let off on the throttle.

and ALWAYS i need to prime the bulb,after i shut the engine down the bulb goes soft within minutes,im thinking its an air leak somewhere.
thats why the strong gas smell always
mike

When you say black coal like pieces, were they hard as a rock and not just back oil/grease? If so those are little pieces from your piston crowns caused by detonation & overheating!- if not sure check it out again. AND get a small light and look at your pistons through the spark plug hole.

OK- so when you said an "air leak"- if there is one it would cause air bubbles in your gas which is bad but would not cause a gas smell unless it's so bad gas is leaking out- only way for it to smell that bad is if there is gas coming out of a leak, exhaust, or very heavy from the carbs. (the drip pan there is to catch the start up drip)

You need 3 things to go- gas, spark, and compression- one of the three is missing after your first run. Start with the fuel lines, pump, and carbs but i'd also check your piston crowns....

AND i'd check for bad spark too...bring a timing light with you, when you can't get it to rev in idle put the light on each wire and see if you're getting spark. If not it could mean a bad wire/ignition part.

 

[ClassyGlassy]

Re: 1985 merc tower of power hard to start

replace the primer bulb like I previously stated! As well as the fuel line connectors that go to the motor and to the tank. Do you run a hard mounted tank in the boat or the small temporary cans? My boat was having the EXACT issue and it was a faulty connection at the can sucking air and losing prime. A few months later it started doing it again and this time it was the connection at the motor.

Rebuild the fuel pump, replace each connection, replace the fuel line, replace the primer bulb, and install a fuel filter before the primer bulb.

I used a $10 clear glass filter from Autozone that is cleanable, a $30 fuel line/primer bulb assembly from Wal-Mart, $10 Mercury connectors, and some new hose clamps.......you can't beat that investment alone!

I can't remember how much the rebuild kit was for the pump but was very minimal.........

 

[ClassyGlassy]

Re: 1985 merc tower of power hard to start

and I'm willing to bet the spark plug that was the cleanest was #1 or #2 as they are the closest to the top........the bottom cylinders run a little more rich because of gravity!

 

[ClassyGlassy]

Re: 1985 merc tower of power hard to start

and run the Champion L76V spark plugs.........do it! Don't buy something else because it simply works.

 

[quantumman29]

Re: 1985 merc tower of power hard to start

I was told to run the ngk buhw plugs in the engine,
I use a plastic 12 gallon gas tank on the boat
I do believe the fuel lines may be leaking and or not very tight,the line from the new gas tank to the bulb are brand new,I will replace the line from the bulb to the engine this weekend,and then run some sea foam or mercury carb cleaner thru the engine,

I believe the lowest spark plug was the cleanest,the other 5 had some black mucky stuff in the little hole and around it,the gap hole of the plug im talking about,is where the black stuff was...

if all this dosent eliminate the problem I will find a quality merc mechanic and let him use his expertise on repairing the engine as im no mechanic by no means and I dont want to screw anything up or make it worse,i can do basic repairs but nothing intense,plus I work 6 days a week and im on 24 hour call 7 days a week,

I am sure the engine is in great running shape and the problem is most likely minor stuff or it wouldnt run at all,I will do the simple stuff myself then seek pro help at the end,
I live in jacksonville florida so if anyone wants to work on the engine,the job is yours...

thanks,
mike"quantumman"panek

 

[ClassyGlassy]

Re: 1985 merc tower of power hard to start

I'll say that the BUHW plugs are my second recommendation for plugs. You were given good information.

I agree that it's something minor as the motor will run when the conditions are right. Rebuilding the pump is so simple my 12 year old daughter could do it.........that almost sounded like an insurance commercial.

The seafoam is always a good idea, but probably not as needed as the fuel system maintenance you will perform.

Keep us updated on what it was.

Paul

 

[quantumman29]

Re: 1985 merc tower of power hard to start

I will replace all the lines and connections,new bulb,make sure everything is very tight,then take the boat out this sunday run her for a while, turn it off,let her sit for a while and start her and see what happens,

by the way,im running this engine on a 17.9 ft glasstream bass boat,this past weds I met my buddy on the st johns river in palatka florida,he was to show me some spots to fish for the tournament as I was never on the river before,

he has a 2010 21 ft skeeter bass boat with a 225 mercury on it,
I had 6 gallons of gas on the boat,myself(195lbs) my wife(115lbs) 3 batteries,half full livewells,an 82lb thrust motorguide greatwhite trolling motor and tackle and rods and gear,

my boat stayed within 200 yards of his skeeter while running wot, my tach was reading 5800 rpm and gps told me we were hitting 59-62 mph, im running a stainless steel prop on the motor.

with just me on the boat a few weeks back,with the aluminum prop the boat went 59mph
im thinkin with me alone and the stainless prop i may hit 65!
that 115 tower is BAD ***!!!!

MIKE

 

[arsenalpsu]

Re: 1985 merc tower of power hard to start

Yep , best power to weight ratio of any out board ever made, even today. (i have an 84 115 tower) If you trim her out a bit you might get a few more MPH, you'll loose some handling but increase your top speed...good for those long runs.

PS.... I'd stay away from WOT until you figure this out, if she's running lean nothing will destroy an inline faster than lean WOT, and make sure you replace the impeller every other year.

 

[ClassyGlassy]

Re: 1985 merc tower of power hard to start

The power to weight ratio of the Tower is unsurpassed and hasn't been matched since! It is one of the greatest motors of all time...........

It's a proven fact that you can run a different pitched aluminum prop to get the same rpm/speed as a stainless prop.

 

[ClassyGlassy]

Re: 1985 merc tower of power hard to start

Gmta

 

[quantumman29]

Re: 1985 merc tower of power hard to start

ive heard nothing but great things about these towers,this is the 1st one ive owned,I never even knew anything about them,ive done research on them and found out that in 1985 when there were restrictions on bass boats for engine sizes,mercury came up with these tower of powers in 83,or 84 for allison speed boats,supposedly there were never engine sizes on these motors as they were just known as inline sixes,

accordingly,there were no 6 valve engines for bass boats in 84,or 85 and thats when the v-4 engines were designed,most bass boats had engine ratings of 140 on them ,mercury started putting these towers on high end bass boats and placed a 115 or 90 hp sticker on the engines,in reality these engines are 115 is equivelant to a 140 hp,and the 90 is equivelant to a 120 hp, I dont know how true this is,but i do know that there isnt a 90,120,140,or150,that my boat wont keep up with or blow away,

my 1999 nitro had a 150 nitro series merc on it and my top speed with that boat at wot was 52mph,and the hole shot was horribly longer then that of the inline on my boat,im up on plane in seconds with the inline,like i said,its bad to the bone,im impressed big time!

I love when im alongside 150's and they think im in an old peice of crap boat with an old junk 115 hp engine,I blow em away....lol

mike

 

[ClassyGlassy]

Re: 1985 merc tower of power hard to start

 

[ClassyGlassy]

Re: 1985 merc tower of power hard to start

I bet you wouldn't along side this 150