'72 Mercury 110 Help

[FF211]

Hey fellas, been browsing the site for a while and finally decided to make an account.

I'm currently working on a 1972 Merc 110 9.8hp with a Thunderbolt ignition that I recently acquired. I've really never worked on motors other than a couple dirt bikes when I was a kid so my experience level is minimal. The motor had not been started for ~10yrs prior to me having it but I have since at least got it running. So far I have changed the spark plugs, replaced all the fuel lines and connections, replaced the impeller, new gear oil, replaced the float bowl cover, and a few gaskets here and there along the way. Everything else looks to be in good condition given the age, except for the wiring, of which the coating is basically disintegrating.

I have now ran into two issues that are beyond my knowledge of how to fix.

1. The water coming out of the telltale seems excessively warm. I'm getting a relatively solid stream with decent pressure though.

2. The motor will not stay running under about half-throttle. I have to start it on full-throttle and after a minute or so I can back it down to around half but if I get much below that it will die. Cold or hot, with or without the choke, it will not start or stay running on low idle.

I'm really looking to keep my investment into this fairly low due to the age and cost of possibly buying something that actually runs solid. Any advice is appreciated.

 

[tpenfield]

Sounds like a fuel flow issue. I'd remove the carburetor for a good cleaning and you may have to rebuild it, since it had been sitting so long.

 

[MTboatguy]

I own 2 of these same motors a 69 and a 71, if it sat for that long, the carb needs to be taken a part and cleaned, the float is sinking on you causing your problem, so in reality it needs to be rebuilt as well as pick up a new float for it and then it should run fine. Let me check in a few hours, I might have a good float around here for one.

 

[FF211]

Carb has been taken apart and cleaned. I bought a carb rebuild kit from old mercs along with the float bowl cover when I had to replace that. So all of the gaskets (that's what the rebuild kit consisted of) have been replaced. The float levers have been adjusted to the measurements in the diagram provided with the kit, 13/32" for the primary and 3/64" for the secondary. The float seems to be fine, no obvious damage to it or the spring. I will attach pictures for reference.

Also, the SN for the carb is KB11A if that helps at all.

Maybe the idle and high speed needles need to be adjusted?

 

[FF211]

Low idle issue is solved. Just had to adjust the idle needle

Still need to fix the cooling issue of water being hot coming out of the telltale.

 

[tacx]

Not sure how hot the stream should be? I have never actually felt mine while running, but it is running through a hot engine for cooling, so I imagine it should be at least warm.

 

[FF211]

I only mention it because I haven't found any kind of solid answer and I've read that if it's excessively hot it can mean one or some of the passages through the powerhead are blocked. I haven't been able to find a diagram or anything of how the water actually flows through the block either and I've heard the bolts are notorious for breaking so I'm just trying to find out if it's necessary or even worth taking more things apart or just run it as is.

 

[tacx]

I was out fishing yesterday with my 1970 110 9.8hp. I felt the tell tale and yes it was hot. Not hand burning hot but pretty hot. Others may have a method to check engine temp with a temp gun?

 

[FF211]

Maybe these just run "hot"? I think I'm just gonna leave it as is. If it blows up on me, oh well. Hopefully I'm not too far out from the dock if it happens haha.

 

[racerone]

Haha ,----these motors use a plastic washer at the top of the water tube.----On severe overheat they melt over the tube and block the water flow.----I can not inspect this for you so you decide on this simple inspection job.