Johnson 50hp SPL 1998 Speeding up & slowing Down

Hi , I have a 50hp Johnson 1998 on a 4.75m center console ally boat the motor go,s fine up to 10kts but if you accelerate a little more it just climes up to 25 knots & then if decelerate it just slows back down to 10 knots . I can not seem to sit on a speed in between 10 - 25 knots I can power up from 25 to 31 knots & go from 2 to 10 knots There's just no middle speed to sit on. There is a fuel leak come out of the front of top carby which is more blue like Oil which you can see a light dribble down the back of the leg.
Could this be the problem.

I have Just brought this Boat i have used it 4 times & i was not happy with the wiring in it so I rewired the hole boat putting a dual batter system in & now my Tachometer is not working . Reading a lot on this Forum I think i mite be some thing wrong with the Regulator/Rectifier but i can not take it in to get fixed for 4 weeks & I would like to use the boat to go crabbing with my dad this weekend. Would i do any damage with it not working. ( I no it will not charge my Batterys but i just want to take him out for a day.)

Re: Johnson 50hp SPL 1998 Speeding up & slowing Down

rebuild your carbs, with a rebuild kit, also test recifier, both are covered here.

http://forums.iboats.com/forumdisplay.php?f=31

Re: Johnson 50hp SPL 1998 Speeding up & slowing Down

I recomend an OEM manual(not Clymers/Seloc) it will tell you exactly how the test a rectifier and other possible causes for the tach not working.

A common cause of that is the tach has to be grounded to the engine, alot of people ground it to the boat battery and leave an open circuit.

The reg/rec only deals with the battery, the motor will run fine with out it working

But if you are gonna work on the boat get the correct OEM manual, they pay for themselve the first time you open it.

And I concure with TD, classic dirty carb symptoms.

As to hurting the boat, generally when a carb gets dirty it is 1 carb so the other cylinder isn't getting the gas it needs and since the oil is in the gas you could be running one cylinder with no lube and 1 cylinder is hitting and one is dead so it really stresses the crankshaft.

Re: Johnson 50hp SPL 1998 Speeding up & slowing Down

Thank you very much for your quick reply,s & all your help
Regards J,seas .

Re: Johnson 50hp SPL 1998 Speeding up & slowing Down

Disconnect the rectifier before running it.

Let us know what you find from the FAQs provided by Tash.