1970 MERC 50HP Issues

[Psychonosspaz]

So I just bought an old Las Vegas Trihull that came with a 50HP Merc (presumably also 1970)...a few issues....from the start the motor starts right up and I let it idle high then bring it down shift into forward drive and go....never any issues while at full throttle...but once I stop and shut her off to troll my small motor I have issues getting it restarted....normally it's a horrible problem of reprimimg bulb, Playing with the forward assist and choke....if I can get it into gear without it dying I'm good to go, but normally it just keeps stalling out going into gear if I can get it restarted....previous owner told me about the dying at idle but that it was easy to restart....this is my first boat so I have no idea what to check or do first....last owner said he just changed out the impeller and water pump? That's problem one....

Problem two is the throttle is extremely difficult to push once you get past about 70 percent....it's like the last 30 percent had to be shoved with a lot of power to get it down......

Please help a new boater guys! I don't want to get jacked by a mechanic

 

[jimmbo]

On the old MerControl, all the go-go happens in the last 30% of the lever movement, so the load against the cable increases
As for the stalling... it might just be an idle speed adjustment is needed, of the idle mixture screws need adjusting. Or the carbs are in need of cleaning, inspection and adjustment

 

[Psychonosspaz]

On the old MerControl, all the go-go happens in the last 30% of the lever movement, so the load against the cable increases
As for the stalling... it might just be an idle speed adjustment is needed, of the idle mixture screws need adjusting. Or the carbs are in need of cleaning, inspection and adjustment

I guess I'm curious why it runs fine cold, both idle and WOT, but then has a hard time once warmed up idling and restarting? Could this be the carb? Previous owner just did water pump and impeller

 

[MH Hawker]

the older ones i had most all ways needed a bit of choke to richen it a bit to start

 

[GA_Boater]

How strong is the spark and check compression? Is the gas old?

It wouldn't hurt to rebuild the carbs and fuel pump.

 

[Psychonosspaz]

How strong is the spark and check compression? Is the gas old?

It wouldn't hurt to rebuild the carbs and fuel pump.

Are these easy things to do? Have never worked or troubleshot s boat motor? If it's not too complex I could attempt it....how would I check spark and compression? Could you direct me to where I could buy a rebuild kit for the carb? How hard is it to do? Special tools needed? What's involved with fuel pump? Filter pry could be changed as well

 

[GA_Boater]

What's the serial number of the motor to find the right parts.

To check compression, rent a compression tester at a local auto parts store - Several like Auto Zone have a free rental program. Remove the spark plugs, and using the right-sized adapter, thread the tester into one of the spark plug holes. With the key off and in neutral, use a jumper on the solenoid and spin the motor over until the tester gauge stops increasing. Write down the number, zero the gauge and continue on with the rest of cylinders. The readings all should be with 10%.

To test spark, when you rent the compression tester, buy a spark tester, about 10 bucks. Connect it to a plug wire and the clip to ground. Crank the motor with the key or have some one help. The spark should jump about 7/16" or so and be a bluish white spark. Check each plug wire.

 

[GA_Boater]

A spark tester looks like this.

 

[Psychonosspaz]

Thanks