1971 Merc 110 (9.8 hp) won't hit a lick!!!!

[bktheking]

Re: 1971 Merc 110 (9.8 hp) won't hit a lick!!!!

Not sure what you mean "carb isn't sucking fuel from the bowl". The carb doesn't suck the fuel, the reeds/piston movement causes that. Couple of things with these carbs:

1-Pull the cover on the top, underneath is a screen, check to make sure it isn't plugged. Be careful reassembling not to overtighten the bolt.

2-The float height (it isn't the traditional bowl type setup) has to be spot on, I have instructions how to check it for proper height if you need it. Set one way it won't allow fuel in, set another and it will shoot fuel out the relief hole, they can be tricky to get spot on.

3. There is an air orifice tube in top of the carb, they can get small particles in them throwing off the mix, they won't idle to save their lives if they are dirty. Unscrew it and make sure it's crystal clean.

4. Pull the bottom screw to reveal the jet, make sure it's clean.


Now on these carbs, going from memory, screwing in the idle screw richens the mixture, out leans- opposite to johnnyrude (someone else should confirm this, all memory at this point)

 

[EN2]

Re: 1971 Merc 110 (9.8 hp) won't hit a lick!!!!

How does this ignition system work without condensers?

 

[bktheking]

Re: 1971 Merc 110 (9.8 hp) won't hit a lick!!!!

These motors have a stator instead of condensors, it's a hybrid of points, coils and a stator, amazing system actually if it's all in good shape. The stator charges the coils and points servers as the spark triggers, however if you get a look at a set of points on this system, the points surface is 3x the size of standard points due to the high voltage.

 

[EN2]

Re: 1971 Merc 110 (9.8 hp) won't hit a lick!!!!

Thanks for the reply, I am having trouble getting my head around this. doe the spark occur when the point close? opposite of what most of usare used to. Yes those point contacts are huge.

 

[bktheking]

Re: 1971 Merc 110 (9.8 hp) won't hit a lick!!!!

Everything is opposite, spark occurs when the system grounds, so yes when the points close. Stop switch is normally grounded, motor stops when ungrounded. If you look at the CDI tests it makes sense, you need to ground the points trigger wire to check for spark (when you quickly touch the wire to ground it will spark) , it actually does work, that`s how I tested it. I still got spark so the only thing left was the insulators like this post. Once they were replaced everything started working again.

 

[EN2]

Re: 1971 Merc 110 (9.8 hp) won't hit a lick!!!!

Thanks for the explanation.

 

[RandyJ]

Re: 1971 Merc 110 (9.8 hp) won't hit a lick!!!!

I tell you guys one thing about this motor and this thread... it made me totally re-learn everything I ever figured out about outboard ignition. This whole damn thing is backwards!!!

 

[RandyJ]

Re: 1971 Merc 110 (9.8 hp) won't hit a lick!!!!

Not sure what you mean "carb isn't sucking fuel from the bowl". The carb doesn't suck the fuel, the reeds/piston movement causes that. Couple of things with these carbs:

1-Pull the cover on the top, underneath is a screen, check to make sure it isn't plugged. Be careful reassembling not to overtighten the bolt.

2-The float height (it isn't the traditional bowl type setup) has to be spot on, I have instructions how to check it for proper height if you need it. Set one way it won't allow fuel in, set another and it will shoot fuel out the relief hole, they can be tricky to get spot on.

3. There is an air orifice tube in top of the carb, they can get small particles in them throwing off the mix, they won't idle to save their lives if they are dirty. Unscrew it and make sure it's crystal clean.

4. Pull the bottom screw to reveal the jet, make sure it's clean.


Now on these carbs, going from memory, screwing in the idle screw richens the mixture, out leans- opposite to johnnyrude (someone else should confirm this, all memory at this point)

well, yeah, kinda, but not really. This carb has the filter in a housing above the bowl. No screen that I can see. Fuel flows through the filter into passages that go all the way through the stud which the housing hold down bolt attaches to. This passage has a tee in it that allows the fuel to flow to the needle valve which allows it to fill the bowl below. The bowl is a part of the carburetor casting (molded in with the carburator). The black plastic float rides up and down on a needle looking rod. On top of the float is a spring which operates the needle valve. Near the bottom of the bowl is a very small hole which is the passage for the fuel to the carbureator. At the bottom of the carburator is a slotted screw in plug that covers the jet. The air mixture screw is at another place on the carb. I'm thinking It is the air mixture screw that is adjusted to set the amount of air that pushes into this jet which creates the venturi effect causing the fuel to be pulled into the carburator's throat and thus being sucked into the crank case to be delivered to the top of the piston for that much needed explosion to occur..... I'll get a picture and post it. And, yep... i'd appreciate anything you got to tell me the details of setting float height.
After I get this thing going I've got 3 seriously antique Martin's to get going, one 1967 Ted Williams (McCullough) 9 hp, two game fishers that obviously have fuel system problems (one starts great but runs like crap, the other is hard to start but runs great).... When I get through with that I've got a 1990 90 hp Force that does absolutely nothing when hooked to a battery... then I've got two Mercruiser 140's to figure out, two mercruiser 260's, one 470, and about 6 or 8 more Mercury 50-65 hp's to tinker with.. then I might get around to a couple of old 6 hp Wizzards around 1952 models. No lack of "projects" in my yard.....

 

[bktheking]

Re: 1971 Merc 110 (9.8 hp) won't hit a lick!!!!

I know this carb inside and out, same style on my 6 hp. That spring on the float can even have an affect on fuel flow, it's not that simple.

http://johnsoldmercurysite.com/whitepapers/CarbService.pdf

This pdf explains it all. The carbs are even different from johnnyrude. With a johnnyrude a typical starting point for the idle mix screw is a turn and a half. On these it's half a turn. If you haven't got 1/2 a turn set chances are it's out too far thus too lean and probably why it won't run.

 

[bktheking]

Re: 1971 Merc 110 (9.8 hp) won't hit a lick!!!!

Oh ya and btw, hope your choke is installed and working when you are trying to start it, these 2 strokes WILL NOT START without a proper working choke, that's what causes the "suction" as you put it for cold starting.

 

[RandyJ]

Re: 1971 Merc 110 (9.8 hp) won't hit a lick!!!!

Oh ya and btw, hope your choke is installed and working when you are trying to start it, these 2 strokes WILL NOT START without a proper working choke, that's what causes the "suction" as you put it for cold starting.

yep... no problem with choke... Before the ignition problem this motor ran better than new. It was actually a tip for a job I did. I only had to put in an impeller then I was ready to ride!

 

[RandyJ]

Re: 1971 Merc 110 (9.8 hp) won't hit a lick!!!!

Good News... so far.... got it running. The idle mixture adjustment screw seems to be pretty sensitive. It ran really good after ONE MORE cleaning.... got 3 motors running today!

 

[bktheking]

Re: 1971 Merc 110 (9.8 hp) won't hit a lick!!!!

good job, glad it's back up and running!

 

[smanb098]

Re: 1971 Merc 110 (9.8 hp) won't hit a lick!!!!

Real easy to test the stator if you have a DVA, disconnect the green wire and connect the DVA on AC, check for 450V+ when cranking.

These are what bad blocks look like, a motor I had to change them on last summer, notice the split in the center, not normal.

If you go to the CDI website there is a test breakdown on the entire system that WILL tell you what's wrong, it's systematic troubleshooting at its best.

Hi,

Would you happen to have the link to the CDI wbsite. I have a 9.8 that I want to go over. Its completely dead in the spark department.

Thanks in advance.

 

[gatorfan6908]

Re: 1971 Merc 110 (9.8 hp) won't hit a lick!!!!

Waking the dead I see... Wow this thread is old! Sry tho, I have no help for a link. Try out google. Sure u can find it there!!

 

[RandyJ]

Re: 1971 Merc 110 (9.8 hp) won't hit a lick!!!!

I got the insulators for that motor directly from CDI... fixed my problem. Not much to the ignition system on these motors. If the circuit is not complete through the stop button it won't have spark at all. These motors have an unusual kill system. Rather than grounding out the spark the kill button functions by opening the circuit which kills the spark through the coils. In other words, if the wire to or from the kill switch is broke it ain't gonna run. Disconnect the kill wire at the coil and check for continuity through the wire all the way to the stator with an ohm meter.. could be broke wire or bad contact in switch (clean contacts with sand paper and make sure wire is making good contact). The site is CDI Electronics | Outboard Motor Parts | Ignitions | Marine Engine Diagnostic System | Stators | Ignition Packs | Regulators | Coils | Wiring Harnesses

If you're not getting output to the coil but have continuity the only other places to look are points and stator. The points open to break the sparking circuit which is different than other motors where the points opening causes the spark. ( I think I'm right on this, somebody correct me if I am wrong or misunderstanding this system).

 

[RandyJ]

Re: 1971 Merc 110 (9.8 hp) won't hit a lick!!!!

BTW... I my 110 on a 14 ft flat bottom a couple of weeks ago... I weight 170... not much load in the boat and it SCREAMED!!! Almost pushed it too fast...