'73 Merc 9.8/110 revving issue. PHASE MAKER Ignition

[roscoe]

I've got a a nearly mint 9.8 with the "maker" type ignition.

Been using it for 2 years as a kicker/troller.

Same issue since I picked it up.

In reverse, I get good rpm and seems to be reaching max rev's.

But in forward, 98% of the time, I only get about 2000 rpm out of it before it bogs and falls on its face.

On rare occasion, I will get a little more rpm for a couple seconds, then it bogs.

All original. Wiring is in good condition, and have good spark.
Only work ever done to it is impeller, sparkplugs, and a carb cleaning a few months ago.
Have not pulled the flywheel.

Linkage all appears to be moving as it should in both forward and reverse, but obviously, something is wrong.

I really love this motor for its ease of use and is light weight. Have manual, but has not been enlightening for this forward/reverse revving problem.

Would really like to get to the bottom of this, but since many parts are nla, or very pricey, I'm hoping it is something "simple".

Any ideas on what to check would be greatly appreciated.

 

[roscoe]

Re: '73 Merc 9.8/110 revving issue. PHASE MAKER Ignition

Any ideas here?

 

[roscoe]

Re: '73 Merc 9.8/110 revving issue. PHASE MAKER Ignition

nothing ?

 

[MH Hawker]

Re: '73 Merc 9.8/110 revving issue. PHASE MAKER Ignition

It sounds like a fuel issue, did you change the needle and float.

 

[oldman570]

Re: '73 Merc 9.8/110 revving issue. PHASE MAKER Ignition

You might have a bad wire going under the flywheel that is broken or shorting across to ground when the motor timming is advanced. This happens when the wires get old and brittle and are pinched in the passage under the flywheel or a coil might be breaking down. Parts can still be bought for these motor at old mercs.com when needed. JMO
Oldman570

 

[CharlieB]

Re: '73 Merc 9.8/110 revving issue. PHASE MAKER Ignition

Clean the carb, the main jet may be dirty

Rebuild the fuel pump, output may be slightly low

Check all fuel lines and bulb for restriction or air sucking in at a loose fitting or bad O-ring at a disconnect fitting. If the fuel pump is separate from the carb, temporarily install a clear hose between the pump and carb, run the motor and see if any air bubbles pass thru, indicating air. Be SURE to remove the clear hose once finished as it is NOT recommended for fuel use.

The motor is never under 'full load' while in reverse. Full load in Forward demands full fuel flow. I suspect the float bowl is running low and the motor simply runs out of fuel and dies. Cranking to restart the fuel pump still moves enough fuel the motor restarts.

 

[roscoe]

Re: '73 Merc 9.8/110 revving issue. PHASE MAKER Ignition

THanks guys.

I guess I will attack the carb again.
Fuel pump too.

Then time to pull the wheel.

Tank and bulb should be good. I have used 3 different sets, that keep up with the main motor that drinks fuel. (115 tower)

I am getting at least double the rpm in reverse, and can sustain for 5 minutes.

THe bogging in forward will happen almost instantly, within 1 second, as I get to 1/3 throttle.
I can run at 1/4 throttle for an hour.

Thanks for the tips, gives me something to work with.