70 horse 78 Rude

[cowboy_36618]

Hey Yall, new here to the forums, been reading alot of great info. Got myself a decent /clean used 1978 Tidecraft with a 78 70 horse Rude on it,it runs great WOT, just not so great at idling in to put on the trailer. It just dies at idle. I know this may sound like a stupid question, Ive asked people I know about this, I cant get an answer I like so I want to ask yall,(1) "the 6 gllaon plastic tanks its not like the old metal tanks from back in the day when my dad had a boat, so does the little vent on the cap that you take off to fill with gas , does that vent need to be vented or not vented when running the engine ?" I was thinking that it may need to be shut" not vented" so that the fuel pump can make or have a good vacum on the tank to run properlly. I may be wrong so thats why Im asking. (2)Would that have any affect on the idling problem or would that be a carb cleaning/rebuild thing I need to have done ? Guess you can say Im having a blonde moment as the lady folk would say, no offense to the blondes out there, so if any one could help me out with the understanding of the tank thing, I would appreciate the mess out of it. thanks yall. and this is a great site for some great information. I love reading things the folks have posted on here.

 

[bowman316]

Re: 70 horse 78 Rude

I have the same engine in the 81 model, and the same tanks.
You need the vent open when running, to let air into the tank, as you remove fuel.

The idle problem is not related to this thou.
You need to adjust the plastic screw where the romote control lines connect to the engine. There are 2 cables running back to the engine, and where they connect to the thottle body, where are 2 black dials. Turn the upper one, I think, It turning it some way should open the carbs up more, the other way should close them.

You want to open them a hair to improve idle.

when you shift from neutral, the first cable to move, is the shift cable, so this is not the one you want to adjust, adjust the other cable.

 

[tashasdaddy]

Re: 70 horse 78 Rude

"You need to adjust the plastic screw where the romote control lines connect to the engine. There are 2 cables running back to the engine, and where they connect to the thottle body, where are 2 black dials. Turn the upper one, I think, It turning it some way should open the carbs up more, the other way should close them."

^^^^^^^^^^^^^^^^^^^^TOTALLY WRONG!!!!!!!!!!!!^^^^^^^^^^^^^^^^^^^^^

there is an idle speed stop screw on the throttle linkage. it is use to set the low speed of the motor.

also when were the carb last cleaned, and rebuilt?

you always adjust the cables to the motor. once you have the motor running well.

 

[bowman316]

Re: 70 horse 78 Rude

Yea, both ways will do it.
I guess the stop screw is easier.
But i think mine would not go far enough to stop the throttle before stalling out.
I must have adjusted me dial on the cable ten times last season.

 

[cowboy_36618]

Re: 70 horse 78 Rude

thanks fellows, I just bought the boat about a week ago, the man i got it from said , this happen to him when he got it too, and he played with the adjusting screws some til it got better, im usually the type that needs it done right ,rather than playing around with it, he never told me that if the carbs have been rebuilt or cleaned , i do have a service manual now on the engine it got here yesterday, i did look at the section on the synking of the carbs with the measurements of the throttle rod, every things looked ok, I did move the throttle cam roller up to the cam the has the marks on it, it wasnt touching at all. cranked it on the muffs, ran good maybe a little to much rpms on the muffs but i figure that would be diffrent on a load in the water, so i need to put it in to test it, i just havent been able yet to do so, but now i know about the venting of the tank, ill check out the running again soon. and the adjustments i have made this morning. thanks to yall for answering so quik, i hope i can have more fer ya later, ill be here to ask more questions im sure. if this isnt going to do the job on the idling, i will have the carbs looked at, or rebuilt,thanks again.

 

[bowman316]

Re: 70 horse 78 Rude

I did move the throttle cam roller up to the cam the has the marks on it, it wasnt touching at all. .

That is what i was explaining, i moved the cam roller a little above that line, to increase the idle.

But I would put it right at that line, and set the screw to hit the throttle body when it is in neutral.

There is a small gap between the roller and the plate on mine too, only when it is in netural.

If you have to, you can loosen a screw on to change the angle of the roller.

 

[cowboy_36618]

Re: 70 horse 78 Rude

Well I took it back out today, still the same ole bogging and dieing... went fishing anyway, then straight to the man to do the carbs.... when i got there for him to look at it, he done his checking of the cylinders, link and sync and firing, he said it looks and runs good to him " on MUFFS" , I told hime its a diffrent beast in the water... he said he will take it to the water to see whats up. then he will rebuild the carbs if he thinks it needs it, im guessing he is going to do that from what ive read and how its doing. thanks for yalls help .