1984 Mercury 50 HP doesn't rev very high in gear and won't plain out 17' tracker

[KcKiller]

Re: 1984 Mercury 50 HP doesn't rev very high in gear and won't plain out 17' tracker

hey just wanted to put my 2cents in I have the same problem....I rebuilt the carbs, check the compression(all good), carbs ar at 1 ? open (air/mix)..did a stator test, did a spark plug test(gap) test, check the ohms, changed the fuel pump(kit), changed all my hoses.. well as it turned out all checked out well... I was at the end of my rope and ready to step off the chair..lol when someone asked if I had check the rectifier and the switch boxes.. well that my friend is probably your problem... check your boxes and conduct a stator test... also check the wires from the trigger assembly make sure none of them are corroded... and if this does not work well I suggest that you take it to a boat mech and he will diagonose and do all these test and let you know what your problem is ?. All for about 50 to 65 $$$$ at least you?ll know what you need to work on.. now if your like me and just hate going to the shop? try doing it yourself like I did? at the end of it all you?ll know your motor inside out like I do now?lol oh also get a manual it?s a allot of help? check the high speed switchbox

 

[This_lil_fishy]

Re: 1984 Mercury 50 HP doesn't rev very high in gear and won't plain out 17' tracker

Rebuild your carbs.

Its reving in N easy because there is no load on the motor.

I learned recently that the inlet needles are an issue. My carbs were done last fall and they are already acting up. I was informed that the black tipped inlet needles are crap.

This is true. The merc. kits come with all steel needles now, and they work much better. Also replace your floats if they are foam, as they suck, the new floats should be plastic. Good luck...


Ian

 

[CharlieB]

Re: 1984 Mercury 50 HP doesn't rev very high in gear and won't plain out 17' tracker

Spark test

A weak high speed winding in the stator will limit high speed power.

Test the stator, Ohms test each set of windings then DVA test cranking and running output.

DO NOT assume anything, DO NOT purchase any electrical parts until proven bad.

 

[X53Gunner]

Re: 1984 Mercury 50 HP doesn't rev very high in gear and won't plain out 17' tracker

Ok I just rebuilt my carbs I noticed on one of the two side by side rubber flaps where fuel goes in that one of those was pushed into the hole and not flapping free. Anyway I blew everthing out with air and am wanting to go to the lake and test it. The small airfuel mixture screw is supposed to be 1 1/4 turns out I believe and I'm not sure what the long silver needle is supposed to be set at? Thanks guys!
Scott

 

[X53Gunner]

Re: 1984 Mercury 50 HP doesn't rev very high in gear and won't plain out 17' tracker

Well I rebuilt the carbs put the new floats in took it for a ride and it would plane out but almost wouldn't. I fill my live well with water to simulate a fishing partner and it would plane off. I gotta believe the motor should rev higher then what I'm hearing. Am I crazy to think a 50 merc should plane out a 17 foot aluminum flatbottom bass tracker with 2 people in it? I might just have to bring it in and have the electonics portion of everything checked over this week.
Scott

 

[sportsmanphil]

Re: 1984 Mercury 50 HP doesn't rev very high in gear and won't plain out 17' tracker

I have a 175 TXS Tracker with a Merc 50. It will scoot on down the water for the size boat it is. Mine gets on plane easily with two adults and two kids. Ive even pulled a tube with no issues. I have not GPS'ed it but I estimate 30 - 35 mph

Do you have a tach? Mine isn't accurate (it jumps a bit) but it runs around 6 - 7K RPM.

Is the motor depth set right? The cavitation plate should be flush with the bottom of the boat.

 

[jeffdjpeat]

Re: 1984 Mercury 50 HP doesn't rev very high in gear and won't plain out 17' tracker

i have a 16 foot bowrider, all fiberglass, with a 1986 60hp merc, and according to GPS im running 30-34 mp/h with 2-200Lb men on board. your boat should plane out easy. i was carrying 2- 5 gallon fuel tanks full, and more junk. i am also using a planner board on my motor, it wouldnt plane out with a heavy load without it, but it would still push 26 mp/h. before i installed the planner board.

 

[seany150]

Re: 1984 Mercury 50 HP doesn't rev very high in gear and won't plain out 17' tracker

my 7.5 merc does exactly the same, revs high in nuetral, like it should but in gear sound likes its not even quarter what the revs should be, and really bloody slow. i was overtaken by a 3hp in a smaller lighter boat than me!! also in reverse sounds like it revs more but doesnt really go anywhere. boths plugs are producing bright blue sparks and everything seems to be ok, just not enough power in gear?

could a spun prop be the problem, under load the prop isnt working efficiently and slipping and thats why the revs appear to be lower and slower speed?

i know my engine should be going a hell of a lot faster because theres a video of the exact engine pushing a boat bigger than mine with 2 people in it and planing!, mines pushing it slower than a seagull would!

 

[This_lil_fishy]

Re: 1984 Mercury 50 HP doesn't rev very high in gear and won't plain out 17' tracker

Tough call, if compression is a bit low you may not have full HP, or if the prop is wrong for your boat then no it wouldn't run super well. I have a 14' fiberglass that is pretty heavy for it's size....and planes out...but takes a bit. Certainly not going to win any races with it anyhow.

Ian

 

[X53Gunner]

Re: 1984 Mercury 50 HP doesn't rev very high in gear and won't plain out 17' tracker

Well to keep you guys posted I brought it in to the boat doctor. He is going to check all the electrical for me and hook it to a dyno and put a load on the motor. We also looked at my prop and its a 19 pitch we checked a prop calculator with rough weight guess's and it showing I should have a 14 to 15 pitch, that is one big difference. I need to find a used one to try before I make that big of a jump with a new one. Will keep you posted. Thanks again guys for sticking with me on this!
Scott

 

[X53Gunner]

Re: 1984 Mercury 50 HP doesn't rev very high in gear and won't plain out 17' tracker

Also there is no RPM Gauge on my tracker as its an older model. Can I add a tach to the 84 merc? If so where and what kind of tach should I get. I hooked em up to cars and bikes all the time I guess a boat motor can't be much differn't. Don't wan't to get crazy with money but a decent tach would be nice. Thanks again!
Scott

 

[X53Gunner]

Re: 1984 Mercury 50 HP doesn't rev very high in gear and won't plain out 17' tracker

Well I thought I would update! It was never the motor. I had a 19 pitch prop and droped to a 13 pitch like mercury web site calls for on my boat and she runs like a rocket...LOL Thanks for all the help. I just wanted to post what the problem so maybe other people may benifit from it. Take care guys!
Scott

 

[Tech]

Re: 1984 Mercury 50 HP doesn't rev very high in gear and won't plain out 17' tracker

Propping is everything!

 

[crazyclam]

Re: 1984 Mercury 50 HP doesn't rev very high in gear and won't plain out 17' tracker

yea I beleive I have the same boat, the tournament TX-17 its a flat bottom tracker with the 50hp 2 stroke merc on it.....

FYI - Those plugs are flat by design and have been around for years....
- The local boat shop guy here solves a lot of problems with props!!!


glad to see your moving fast now, so now you can take that girl out that weighs what your livewell does....

 

[dirty mechanic]

Re: 1984 Mercury 50 HP doesn't rev very high in gear and won't plain out 17' tracker

Before you do anything check that compression no piont in tuneing up a dead engine!

 

[chefguy2000]

Re: 1984 Mercury 50 HP doesn't rev very high in gear and won't plain out 17' tracker

Ok. I have the same motor same problem., and I fixed it. I thought the same things must be a carb problem or stator. This is what i found. If your fuel lines on the engine are like mine...change them and put good hose clams on them, mine were sucking air at High rpms causing the floats to empty and stick(I will change them to plastic after reading this thread thanks). It would then act as if it were running on two cylinders I fixed the fuel line issue. the problem then arose that at high rpm's it would run for five minutes then the rpms would reduce by a bit until i gave the bulb a squeeze then come back on line (fuel pump). As far as not coming on plane...I also have a tracker. the bottom is filled with foam that soaks up water. it needs to be removed i rebuilt my boat this fall and remove about 200# of water soaked foam. You can replace ti. I left mine empty in the back and left all the foam in the front.
Check your prop someone put a 13 pitch on mine. Your prop acts like a govenor too high of pitch and the engine will not reach maximum RPM's too low and it will over rev. There are several places on line that will help you fit a prop but you really need to put a tach on it to get the optimum performance. Mine harness has a grey and brown wire that hook up to a tach. I put and 11 on mine it runs about 30 mph now, planes out great. I have two large batteries that are for my electric trolling moter i moved those to the front. I also put a in a console as mine it was a tiller. I have not had it in the water since the console install but it ran like a champ after all the other fixes...bottom line this boat was "abused" for many years and it just needed someone to take care of it I do have before and after pics if yu would like to see them. I do have one question about shifting. This motor has issues shifting into reverse. Any help would be appreciated.

 

[falcon305]

Re: 1984 Mercury 50 HP doesn't rev very high in gear and won't plain out 17' tracker

ive read all your response and i haved the same problems. the only diffrence is that i troubeld shooted everything. your problem is one of the three. # 1 check your compression on all cyclinders. the must be over 90 psi. if lower psi the motor is no good and your going to have to rebuild the motor. wich its not worth it. # 2 check to see if your getting spark on all your cyclinders. # 3 you could have internal cracked ground wire. meaning that the wire wire could look new but it could be damange in the inside. i bet one of these problems could be your problem. (remember check your compression!) and spark! let me know what happens