Mercury keeps bogging down

[crookedmullet]

I've got a 1991 80hp Merc. 3-cylinder that keeps bogging down. Does the ignition coil have a correlation with it bogging down? And how can I check it before buying new ones? I've replaced fuel tanks, fuel lines, fuel filters, primer bulb, stator, switchbox, voltage regulator and rectifier. <br />The carbs were also taken apart and cleaned not too long ago. <br />When the engine is bogged down and I push in the choke, shouldn't it go back up to speed cause it's pumping more fuel into the carbs, cause nothing happens? The primer bulb never looses it's pressure during the whole process. <br />Any info would be great!

 

[JB]

Re: Mercury keeps bogging down

We need a more detailed description of your symptoms, mullet.<br /><br />"Bogging down" means too many different behaviors to most.

 

[crookedmullet]

Re: Mercury keeps bogging down

JB-<br />I'll have the engine trimmed up doing 30 mph, over a distance of 2 miles, when all of a sudden the rpm's drop. It sounds as if my carbs are opened but I'm sucking in too much air. <br />I forgot to mention this earlier, I noticed my fuel consumption was a lot higher than in previous outings even though I didn't go any great distances. What are some things to check to finally get rid of this problem?

 

[Laotzu]

Re: Mercury keeps bogging down

Even tho you cleaned the carbs in the past, there might be some gunk in one of them. Try pulling the plugs and see if one of them is oily and black vs. the other two<br /><br />Jerry

 

[Bob H.]

Re: Mercury keeps bogging down

You didn't say if the engine starts right back up. If dumping fuel through the choke didn't help there's possibly an electrical problem when the engine heats up - usually a cracked coil.

 

[crookedmullet]

Re: Mercury keeps bogging down

The engine does start right back up again. What kind of test can I do to find out which coil it is, and would it be better to replace all three so I won't have that problem anymore?<br /><br />On another note, I am always nervous about making adjustments on the carbs. At idle, the engine runs smooth, but when I put it into gear, at low rpms, it sputters and sometimes will shut off when throttling up. Where on the engine can I make proper adjustments?

 

[Mike Caspari]

Re: Mercury keeps bogging down

Resistence check? Spark tester from the local auto parts house? I haven't used these methods to check outboard coils but the guys on here seem to know what they are talking about. I think the spark tester is cheap and will give you an indication of discrepancies among the coils and firing. you may get some spark, but "how much" is the key. I need to check mine this weekend.

 

[crookedmullet]

Re: Mercury keeps bogging down

I just briefly talked with one of the mechanics that I deal with, he immediately told me, without any hesitation, that it is the sensor trigger(sensor coil), which is located below the stator. Unfortunately, I couldn't get anymore info, I'm busy here at work. I have no idea of what this part does or how I can test it. My manual doesn't mention any sensor triggers. Is there another name for this part and can anyone tell me how to test it? <br />I'd like to thank everyone for their help. It's a definite advantage having everyones insight, I hope to get to the bottom of this soon.

 

[Laotzu]

Re: Mercury keeps bogging down

Probably means trigger coil. Send a fire signal to the coils as the flywheel rotates.<br /><br />Jerry