Bogging Mercury 60hp Outboard.....What Gives?

[Mercury60]

Hey guys, my 1986 Mercury 60hp outboard has just started bogging pretty bad. It runs fine at idle and full throttle but between 2250-4750rpms it just wants to bog down and stall.

My first thought was great....the carbs are gummed up, but I just rebuilt them! The boat has been running great all season and just started doing this over the weekend. The carbs were rebuilt, and I installed new fuel lines, new fuel pump diaphragm, and new fuel filter in May. The engine probably has 20 hours on it since then.

I always use quality gas with QuickSilver Premium Plus oil and Marine Stabil ....what the heck?

Any ideas on what would cause it to bog down between 2250-2750 but run great at idle and full throttle? Thanks!

 

[Mercury60]

Re: Bogging Mercury 60hp Outboard.....What Gives?

Wow I made it to the 4th page in record time......anybody?

 

[Orbit Express]

Re: Bogging Mercury 60hp Outboard.....What Gives?

If your '86 Merc has gotten you this far, you're doing alot better than many. My 2001 bit the dust, and when I took it to the dealer, they had them stacked up like cord wood.

 

[Mercury60]

Re: Bogging Mercury 60hp Outboard.....What Gives?

If your '86 Merc has gotten you this far, you're doing alot better than many. My 2001 bit the dust, and when I took it to the dealer, they had them stacked up like cord wood.

Thats awesome This was my first boat and I didn't know better at the time. So far I've learned what the letters in BOAT stand for, I've had fuel and cooling issues since day one......

What would make an outboard bog in mid throttle but run great at WOT and at idle?

 

[Orbit Express]

Re: Bogging Mercury 60hp Outboard.....What Gives?

I'd try using premium gas, back in '86 fuel quality was much better than is is today.

 

[Mercury60]

Re: Bogging Mercury 60hp Outboard.....What Gives?

I'd try using premium gas, back in '86 fuel quality was much better than is is today.

I've always run brand name 93 octane with Quicksilver Premium Plus 2-stroke oil and Marine Stabil......

 

[Solomon Shaffer]

Re: Bogging Mercury 60hp Outboard.....What Gives?

You might want to check your fuel tank. I just cleaned the carbs on my 50hp and yet after about 2 runs out it starting bogging again. It turns out that my old gas tanks had a lot of junk in them, and the top carb is missing the fuel strainer. If mine starts bogging, I drop the bowl and clean the jet.

 

[Mercury60]

Re: Bogging Mercury 60hp Outboard.....What Gives?

Good idea to check the tanks, I'll be sure to do that. Here is the tricky question.......isn't the fuel filter supposed to filter out any junk that could come out of the tank?

 

[Solomon Shaffer]

Re: Bogging Mercury 60hp Outboard.....What Gives?

Good idea to check the tanks, I'll be sure to do that. Here is the tricky question.......isn't the fuel filter supposed to filter out any junk that could come out of the tank?

Yes, it is but my situation is proof that some still gets through. My boat has a pump on each carb...the one with the micron strainer had all kinds of little pieces in it and the other one would cause the motor to run poorly. I'm guessing that for better fuel filtering, it would be better to get one of the bigger filters/separators. I just have the little in-line fuel filter.

Of course, if this was the problem, you'd think that it would bog at WOT rather than in the middle.

 

[Mercury60]

Re: Bogging Mercury 60hp Outboard.....What Gives?

Of course, if this was the problem, you'd think that it would bog at WOT rather than in the middle.

Thats my dilhemma....It doesn't make sense to me. It runs great at idle and WOT. Just bogs and dies in the middle.

I'm thinking it is either a flaky spark issue at certain rpm ranges or the carbs are partially clogged/out of tune. Problem is, I'm not to certain how to diagnose either.

 

[avenger79]

Re: Bogging Mercury 60hp Outboard.....What Gives?

i would check the needle settings on the carbs again. otherwise fueltanks as prev mentioned. gunk floats around and starts blocking lines.

 

[Mercury60]

Re: Bogging Mercury 60hp Outboard.....What Gives?

Thanks for the help guys. Dumb question of the day.... Anybody have a link for instructions on properly checking needle settings on outboard carbs? Don't have a factory service manual (I know, I need to get one)!

I come from an automotive background and I'm pretty handy with a wrench but I have to admit, 2-stroke outboards are a completely different animal.

 

[Solomon Shaffer]

Re: Bogging Mercury 60hp Outboard.....What Gives?

The knowledgeable guys around here will recommend that you only buy a factory service manual. I agree with them. But, the cheap manuals can be of some help, at least in my opinion. (They helped me, along with the forum.) If you have mechanical experience, it shouldn't be too hard. I would do a google or bing search.