Newbie and 1973 Merc 110 9.8HP

[scl009]

1973 Merc 100 9.8HP SN 3737944

I'm new to outboard motors, I've dealt with a number of small engines (lawn mower, pressure washers, motorcycles etc) but impellers are a new thing to me. Anyways I picked up a 14' aluminum with a merc 9.8 from my brother in law. He was under the impression that the motor would start right up with a carb clean because it had been sitting for a few years in backyard uncovered, but ran well last time used. I took off the cowl and thats where my frantic internet search led me to iboats. I had the apparently common problem of dry rotted wires, which I replaced. I cleaned the plugs and they have good spark, over 1/4 inch. Tried starting it and it would fire up but only run for 20 secs max at full throttle and choke. I pulled the carb and fuel pump and gave it a thorough cleaning. While cleaning the carb I noticed in the center a black plastic cylinder with two arms that stick out onto the sides of the carb body and a hole in the bottom where the valve sticks up and protrudes into the plastic thing. One of the plastic arms has partially craked. Replaced carb and tried again but its worse only run for 5-10 seconds. Thought I would give the points a clean and setting and thought I may have messed up the timing when getting into the rewiring. Tried to static time the motor, but I think I just made things worse so I'll wait and try and retime when my selco manual gets here. I've also ordered a new impeller and fuel pump kit. I did notice at the beggining of the process that the motor wasn't peeing.

Anyways my questions.
1 - Whats the black plastic cylinder in the carb? I searched and tried to find a replacement but couldn't fint anything.
2 - I've read that when the motor doesn't pee that engine overheats and kills. how long does that take? 20secs? So could a new impeller/water pump fix all my problems?
3 - I know I'm gonna put a new impeller so I just went to take off the lower unit, but none of my wrenches/sockets will fit in the space allowed to get the bottom lock nut off. Is there a special socket with a thinner wall for this or something.

Sorry for length
Scott

 

[scl009]

Re: Newbie and 1973 Merc 110 9.8HP

Welp, a new day brings better news. I think this is one of those things where I just had to take a break and start fresh later. I went and picked up a new fuel line and some other stuff for the boat. Came back home pulled the lower unit and flushed the system, water came out of the riser tube and after a few minutes out of the pee hole too. Turns out I was simply using the wrong socket hahaha.

Put it all back together and started her up for the first decent time. Ran for about 2 minutes, some steam/exhaust was coming out of the pee hole (whats the real name for that?) but NO nice stream of water, so I shut her down. So I guess I definitley still need an impeller which will be here on thursday. Was running kind of rough though. doesn't like to be in idle and it seems theres only to speeds fast and slow, no gradual build of power.

Would still like to know what the black plastic thing in the carb is. I'm thinking I could probably remove it without performance issues, but aren't too sure.

 

[aussieflash]

Re: Newbie and 1973 Merc 110 9.8HP

Would still like to know what the black plastic thing in the carb is. I'm thinking I could probably remove it without performance issues, but aren't too sure.

Maybe post a photo of the "Plastic Thing" so we know what you mean....Also go to Crowley Marine for parts diagram,just type in model,year,HP etc.

 

[62 ROYAL SCOTT]

Re: Newbie and 1973 Merc 110 9.8HP

HELL-O and WELCOME I don't have any info.but i thought by now, someone will give info. and help. if going to work any motor always get a manual . i think you can google it i may be wrong. GOOD LUCK

 

[bktheking]

Re: Newbie and 1973 Merc 110 9.8HP

1. Black plastic thing is a float, round and sits in the bowl? You remove that and it will flood gas out the top of the filter housing and start a fire, that's what shut off your gas flow.

2. not peeing don't mean squat, half the time that system is blocked up from all the crap picked up in the lake and merc's are bad for plugging up, make sure the fitting is clear.


The impellers in these motors are quite small. When they break , the fins do a good job of plugging things up in the system. Take it apart and inspect before anything. When reassembling use a zip tie to compress the fins to get the pump back into the impeller housing.

The fingers I think you are talking about on the carb are at the top and connect to a linkage, all has to do with throttle control.

A word on the float- if you have a look on how the float is set on these motors, the adjustment has to be exact, the float system is very senstive to adjustment. Set wrong one way they flood out the top, set too far the other way they starve for fuel. The float setting usually comes with the rebuild kits.

 

[scl009]

Re: Newbie and 1973 Merc 110 9.8HP

Thanks for the help guys,

I've been to crowley marine before from reading other threads, but didn't realize I could just type in year model etc. I kept putting in my serial number like the search box says and would get no results.

Using Crowley I figured out the black plastic thing I was referring to is the Venturi. The Venturi has two little arms on it that hold it inside the throttle body/atomization chamber. Its one of these little arms on the Venturi that is cracked.

So even though it WAS peeing when I flushed the system, and NOT peeing when I ran the motor, I may still have a good impeller and I'm stilll clogged? The fitting everyone says gets plugged up is the one right where it comes out of the cowl?

thanks
Scott

 

[bktheking]

Re: Newbie and 1973 Merc 110 9.8HP

There and the fitting on the block, follow the tube and make sure that fitting is clear.

What # on the diagram are you talking about?

http://www.crowleymarine.com/mercury-outboard/parts/458_40.cfm

 

[scl009]

Re: Newbie and 1973 Merc 110 9.8HP

#21 on Crowley Part Number 63907

 

[aussieflash]

Re: Newbie and 1973 Merc 110 9.8HP

While running just stick a piece of wire in pee hole.They get blocked all the time.Good luck

 

[bktheking]

Re: Newbie and 1973 Merc 110 9.8HP

Got ya, I was a bit confused, that's the throttle shaft, ventury is the the hole in which that shaft sits. If it opens and closes the butterfly like it should I can't see it being an issue although you might want to either find a replacement part of fix what you have. A little trick I also learned about these motors- on a saw horse in a barrel they sit tilted too far forward. If you loosen the clamps a bit to allow the motor to sit more horizontally they run and start much better, it's the design I think. A transom is angled remember.