1978 Mercury 50hp having issues, carbs and trim lock

[KevPool]

Hey folks first time posting here. So here are my problems. By boat runs fantastic out of the gates I can get about 500-600 yards and my motor bogs down to about 10-15 kmh. My top carb was leaking it is model#1050508 version E. I rebuilt the carb and she stopped leaking. Now my bottom one has started to leak so I will pick up the kit and rebuild that tonight. Can this leak cause my motor to bog down like that or might I have other problems at hand? My second issue that I noticed yesterday is my trim kit isn't locking on the bar in reverse I have two other trim kits for this motor how hard are they to change or is there an adjustment I can do to help this lock. Any help would be great as I am new to boating and still learning the ins and outs of outboard motors.

 

[jimmbo]

A flooding carb can cause an engine to bog as it running way too rich. Being each carb feeds 2 cylinders, you are reducing power of 1/2 of the engine, so it will be noticeable.
As for the Reverse lock... You said ""my trim kit isn't locking on the bar in reverse". If your engine has Power Trim, the locking system is disabled(or is supposed to be) as the Hydraulics will keep the engine from tilting up while operating in reverse.

 

[KevPool]

The flooding of the carb is that checking to make sure the float pin is doing its job? they seem to be operating the way they should.The trim isn't a power trim but I am looking at buying one this season. What baffles me is she runs great for the first few hundred yards then chugs right down.

 

[jimmbo]

Could be a fuel starvation problem prior to the carbs. Fuel Pump, filters, hose, primer bulb, fuel pick up in tank, restricted venting of fuel tank

Ok you don't have power trim. There is a linkage assembly from the gearcase that engages/disengages the locking system. Unfortunately, none of the online manuals I can access show the non power trim locking mechanism. Do you have a service manual?

 

[KevPool]

I went and picked up new gaskets for the fuel pump today. I replaced the ones on the top carb yesterday I should have just done them both at the same time. I really hope that's the problem I will try it out when I get home. Thanks for your help jimmbo

 

[KevPool]

No service manual I have been looking online for a download.

 

[KevPool]

Fixed the bogging down problem it was the carbs cleaned them well and put new gaskets in as well as the fuel pump. Still need to fix the trim lock but I can sleep better knowing the thing drives great. Off hand how much fuel does an older motor of that size burn I sure seemed to go through gas fast tonight.

 

[jimmbo]

At WOT, a 5 gallon tank(6 US gal) will last about 50 minutes to an hour. If you pull back on the throttle. say 20%, after reaching top speed the fuel usage will drop about 25 - 30% with just a slight drop in speed. That is also assuming the motor is propped correctly

 

[KevPool]

I found the thread on consumption vs HP was a good read. I have a second 6 gal tank I am going to install in her as a back up. I noticed when I was wot she leans slightly to port thought maybe my trim height wasn't quite right, when I got home I measured the motor placement on the transom and it is 5/8" more to the left. I would have to move it over 5/16". could that small of an amount off center cause that?

 

[jimmbo]

The leaning to port is really a case of weight distribution and/or prop torque. The Prop on your engine spins clockwise when viewed from behind, and following Newtons 3rd Law, the gearcase housing, along the propshaft centerline, is trying to rotate Counter Clockwise, taking the rest of the engine and boat along with it. It can be more pronounced on some Hulls, like Deep Vees, and hulls with round bottoms and soft Chines. Some times a boat will ride level with just a Driver in it, and when a passenger is added, a list occurs. At speeds below 45 mph, it is not much of a concern, at higher speeds it can trigger a boat to Chine Walk

 

[Tjbluewolf]

Hi KevPool. Where abouts did you get your carb gasket kits from? I'm having trouble finding some. I'm on the UK though. Thanks

 

[GA_Boater]

Hi KevPool. Where abouts did you get your carb gasket kits from? I'm having trouble finding some. I'm on the UK though. Thanks

You should start a thread of your own. iBoats is mariner retailer and sells carbs kits, but that probably won't help you in the UK. Finding a local Mercury dealer is probably your best bet.

 

[KevPool]

I picked them up from Avo marine here in Winnipeg Manitoba Canada they had them in stock. I definitely love boating more then 28 years of carpentry lmfao maybe I should open a parts site lmao. But till then here is a link of the shop they can probably send what you need to you. http://www.avomarine.ca/

Cheers mate.