71 Merc 800. Dont know if its running right?

[rtpassini]

Finally got her out on the lake (fixed the gear problem)

but it doesnt seem like its going as fast as it should. it said i was going about 30 mph. but my tach said 3000 rpms (but im pretty sure its not accurate because i messed with the calibration)

how do i know if its right or not?
i attached a pic that shows when it actually starts going. it seems really far forward.


i also attempted to do the sync but when i turned the carb screws...nothing happened? although i was in neutral (was trying to adjust the idle first)

any thoughts?

 

[corm]

Re: 71 Merc 800. Dont know if its running right?

Hi,

The handle shold go a lot further down. You would not be able to see it behind the persons leg. That is about where the motor would start picking up RPM's. That box has a large transition between shifting and speed.

 

[rtpassini]

Re: 71 Merc 800. Dont know if its running right?

it goes further, but thats where the actual speed starts.
so that sounds like its normal.

i know the prop has a lot to do with the speed/rpms. but because im a moron, im not sure if the rpms are right or not. or if there should be more to the motor.

 

[corm]

Re: 71 Merc 800. Dont know if its running right?

Hi,

About the tach, what brand? How many settings or numbers are there?
Is there a decal on the back of the tach? If so, what does it say on it?

You probably have a 17" pitch prop on it. (just a guess)

 

[rtpassini]

Re: 71 Merc 800. Dont know if its running right?

its a teleflex. since i changed the calibration dial, the guys from teleflex said without a dyno, i wont know for sure. the best i can do is find someone with a similar motor and match it up with them to get it close.

 

[corm]

Re: 71 Merc 800. Dont know if its running right?

HI,

I guess I do not understand what you adjusted.
From what I remember the tach has a setting for
4,6,8,10, and 12 pole alternators. Some had a setting for 2 or 4 cycle
and the number of cylinders. Some of the older ones had Alt or pulse settings.
In the 50 yrs I was in the marine business I never needed a dyno to set up a tach. The guy at teleflex gave you a lawyer answer. Merc has box that we used to use to check tach's out with. You hook it up and it would read a certain RPM. They also make portable tachs that you can hook up to your motor and then match up you tach reading. You motor idles best around 900 rpm the butterflys are 1/4 open at about 2000 rpm. WOT RPM's should be 5300

 

[rtpassini]

Re: 71 Merc 800. Dont know if its running right?

theres a little dial on the back that lets you adjust your rpms. but there is no "starting or ending" point. so i dont know how to get it back.
i think what i will do is hook up the old tach and see where that puts me and just make sure hte new tach is the same.

and why cant you live closer! i need a good motor guy near me. everyone around here is not very nice. haha

 

[corm]

Re: 71 Merc 800. Dont know if its running right?

Hi,

Well cool, you have a old tack to use to calabrate it with.
I was thinking you cold borrow one from a friend or something.
I'd forgotten about that style tach.
We are pretty close as the net goes,but is is a drive in real time. Do you boat on the big lake or Winnebago?

 

[rtpassini]

Re: 71 Merc 800. Dont know if its running right?

if you havent guessed it, my boat is still in the "fix it up" process. haha.

but i do go on winnebago with my buddies parents boat. and sometimes on lake michigan (when the waves arent huge)