84 mercury 50 only goes 9mph

[golferboomer]

On full throttle it will only go 9 miles an hour what can be wrong

 

[roscoe]

The boat weighs 7,000 lbs. ?

We need a little bit more info.


Is this a new problem?
Did it run properly in the past?
Did you just buy the boat or motor?
Is the engine revving up?
What are the rpm of the engine at "full throttle" ?

Start with the diagnostic basics.
Check for spark and compression on all cylinders.

 

[Bonus Check]

If your RPM is still up to what it is suppose to be, Check to see if your prop hub is slipping.

 

[GA_Boater]

Did you fix this? http://forums.iboats.com/forum/engi...-outboards/10069044-gas-coming-out-idle-screw

 

[golferboomer]

I just bought the boat and motor it a 1984 bass tracker 17tx so around 1800lbs with everything on it..I have put a new stator,switch box and trigger on it.. I can't tell what the rpms are but it does Rev up

 

[golferboomer]

And if my prop hub is slipping how do you fix that

 

[racerone]

STOP-----You need to do some testing first.----#1 is a compression test.--#2 is a test to see if you have spark on all 4 leads.------If those are good you may have fuel problems .-----If you keep running this motor with one plugged carburetor you may damage a nice motor.

 

[roscoe]

And if my prop hub is slipping how do you fix that

And if it is slipping, you either replace it, or take it to a shop where they will press a new hub into it.

OK, you replaced a heap of ignition parts, did you verify spark on all plugs when you were finished?

Really though, you need to do a little testing first, before spending money on unneeded parts, or causing permanent damage,

 

[GA_Boater]

I am going to make a suggestion.

Stick with this thread and don't start new threads every time you think of some other possibility. So far you have a no spark thread. switch box thread, gas leak thread and now this one. You will be going around in circles trying to do all the things in all four threads. And naturally you will be getting conflicting advice.

So please stay with this thread and follow what racerone advised before anything else.

 

[golferboomer]

130 compression to all 4 cylinders and spark... and both carburetors are getting gas.. it runs great out of water ... I had to replace all that ignition stuff all the wires were bad the boat sat for 5 years before I bought it

 

[Bonus Check]

And if my prop hub is slipping how do you fix that

To test whether the hub is spun or not, make a mark across the prop and rubber hub so that you know where they are matched up. Make sure the marker is waterproof like using a grease pencil. Take the boat out for a spin on the water. Take the boat out and check the marks you made on the prop. If they are still inline, then the hub may be OK. If not inline, the hub is slipping or is "Spun". Have a new hub pressed into the prop or buy a new prop if spun.

 

[golferboomer]

Ok I checked no prop problem. .but I did have gas coming out of the vent screw on the bottom carburetor which is making it bog down.. what should the idle screw be set at on a 2 stroke

 

[GA_Boater]

Have the carbs been rebuilt?

 

[golferboomer]

I am rebuilding them now.. I took them apart to clean them

 

[GA_Boater]

The rebuild kits should have instructions for setting the floats and how to adjust the idle screws.

 

[Silvertip]

Just so you know, any motor will rev up and seem to run fine ( to an amatuer) out of the water (no load) running on only half its cylinders.