Carb rebuild help. 73 85 hp

[amarcil77]

Hey guys I have a 73 85 hp. I did a complete rebuild on my carbs yesterday. It is running good. But I do have a couple questions.

1. What is the ruler for in the kits. I'm sure it is to synchronize the carbs some how, but I can't find any measurements to do it. Not even in the repair manuals.

2. On the front face of the carbs there are to screws that appear to be plugs but the journal s also look like they could be for adjustments. Again I can't find any info on them.

I just want to make sure everything is right before I attempt to time the motor.

Any help is greatly appreciated.

 

[racerone]

Re: Carb rebuild help. 73 85 hp

Adjust so that all throttle plates are closed at idle. They must be closed at idle.--------No adjustable idle jets on these.----Idle fuel is measured by an orifice.---Those screws that appear to be " an adjustment " to you must be tight.----Floats are to be parallel with carburetor body when carburetor is upside down.---Not as critical as some would say.

 

[midcarolina]

Re: Carb rebuild help. 73 85 hp

The ruler is for setting the float height......
Don't know what carbs you have but sounds like you are talking about the slow circuit air/fuel adjustment

 

[emdsapmgr]

Re: Carb rebuild help. 73 85 hp

The two screws on the front of the carbs are probably hiding a machined idle passage internal to the carb. No adjustment there. Make sure the screws are tightened. There is a factory sync and link procedure detailed in the factory service manuals. They are the only one to be working from when performing this adjustment. Check out this website: outboardbooks.com, their official publication website.

 

[crb478]

Re: Carb rebuild help. 73 85 hp

as said the ruler is for adjusting the floats, but just flip the upside down and set them level, all the jets are fixed so there are no adjustments. If you are confident that all jets and passages are clean put the back together and run it.

 

[amarcil77]

Re: Carb rebuild help. 73 85 hp

They are good I put them on and it ran great. Hasn't run smooth since I bought it last fall. The issue I'm having is at idle. When I get it to idle rpm around 600. It starts to stumble. I haven't set the timing as of yet. I just wanted to make sure I didn't miss any adjustments. I'm going to get a timing light today to check it.

 

[racerone]

Re: Carb rebuild help. 73 85 hp

Timing on these motors rarely goes out of adjustment,---It is fixed for the life of the motor.--------What are the results of a compression test ?

 

[amarcil77]

Re: Carb rebuild help. 73 85 hp

3 cylinders at 110 and the number 3 cylinder (starboard bottom) 104.

 

[emdsapmgr]

Re: Carb rebuild help. 73 85 hp

When you say the engine stumbles at around idle, is it akin to a "lean sneeze?" A periodic misfire?

 

[amarcil77]

Re: Carb rebuild help. 73 85 hp

Yes. Occasionally it will shut down. It starts right back up with no choke or increased idle.

 

[emdsapmgr]

Re: Carb rebuild help. 73 85 hp

This is not a spark issue, but a lean fuel issue. A carb problem. A lean sneeze shows up at idle rpm's only. It's a sign that one or more of the idle passages may be restricted somewhat inside the carb upper body. You need to clean the dried fuel gel out of the idle passages again. Be sure to use a cleaner made to dissolve dried fuel gel, like an aerosol Gumout type product. Even though the carbs may look clean, it's hard to tell if the fuel passages in the carbs will actually flow enough fuel when running. You just can't tell visually. Once you get the old dried fuel out of the carb passages, it should smooth out. This restriction can happen after improper winterization, where the fuel left in the carb can dry out over long periods of storage.

 

[amarcil77]

Re: Carb rebuild help. 73 85 hp

After looking at my carbs closely. I think I cost me a carb. In the mouth of the carb there are 5 tiny holes on each barrel. On one of the barrels the center hole is huge. While taking the plugs out of the carb with an awl. I must have went to far and made a huge hole in it.

Now I need to find a 1973 carb. Good luck to me.

Could this be my problem?

 

[racerone]

Re: Carb rebuild help. 73 85 hp

Depending on your location it should not be hard to find a carburetor.-----There is always that " flea-bay.------Can you plug that hole with epoxy or a tiny screw ?

 

[emdsapmgr]

Re: Carb rebuild help. 73 85 hp

You could also put a pair of matched 115 carbs on it. I run a set of 74 135 carbs on my 1979 85 hp ported block. Had to rejet the mains slightly, but it has a lot more power.

 

[amarcil77]

Re: Carb rebuild help. 73 85 hp

Would a 1980 set of carbs fit my 73. Also is there a difference between top and bottom carbs

 

[emdsapmgr]

Re: Carb rebuild help. 73 85 hp

They should fit...but. Yes there are differences in the carbs compared to your 73, such that you may prefer to look for some 78 or earlier carbs instead. 1. The upper carb has the roller, the bottom carb does not. 2. The 80 carbs do not have choke butterflys. Their choke system is different, (the newer system) using a different choke solenoid, some hose plumbing and different side (bypass) cover plates with tiny hose barbs for the choke system. I'd recommend you keep looking for the earlier carbs with choke plates. Those earlier carbs all use the adjustable carb rod linkage, which will make your sync and link setup easier. The 78 and earlier carbs use the same roller setup as yours.