Hey Bigshrimpin!

[garbubba]

I have a mercury question for you. I have an '96 200hp mercury offshore. It has an erratic problem. I'm offshore Monday, boat started great, ran great, all that. Sat at the beach a couple hours & when we left if started fine, took off great & then lost power, max rpm's about 2000, after a minute of two, boom, back to full power, then back & forth again.

This happened twice before but I couldn't make it reoccur.

What do you think?

Doug

[spareparts]

check your primer bulb, make sure its not sucking closed. If it happens again, try pumping the bulb, if it gets better, you know its a fuel delivery problem, probably the bulb, or something tank related. If squeezing the bulb doesn't help, push the key in to choke the engine for just a split second while its running, if it gets better, fuel related, somewhere between the bulb and the powerhead. If squezing the bulb and pushing in the choke don't help(or make it worse) it could be too much fuel, or ignition related

[steplift20]

heres my 2 cents do you have a water sepperator if you do change the filter and see if theres water in it that would do what your decribing

[garbubba]

I did pump the bulb with no change but I noticed it looks a bit rough so I plan to replace it. It does have a water seperating filter too & I haven't changed it this season yet.

Looks like I have some chores to do.

Thanks,

Doug

[spareparts]

all the primer bulbs available are junk at best, no one makes a real good one, I've taken brand new off brand primer bulbs out of the bilster pack and had them leak, crack, or just not pump. If you are going to buy one, I recomend getting one from an engine manufacture(Merc, Yamaha, Bomb, etc). From what I hear, the mercury bulbs with the yellow rings at the hose fittings are the best available.

[THEFERMANATOR]

The BOMBARDIER primer bulbs are also very good with some pretty heavy duty rubber used in them. TEMPO and MOELLER are not really worth the money IMO, even the SIERRA brand isn't that good. The OE's are your best option.

[bigshrimpin]

I did pump the bulb with no change but I noticed it looks a bit rough so I plan to replace it. It does have a water seperating filter too & I haven't changed it this season yet.

Looks like I have some chores to do.

Thanks,

Doug

Try running the motor off a 6 gallon tank with fresh fuel. That always helps me isolate fuel related problems up to the motor. If it runs well on the 6 gallon tank then chase the problem backwards. If it still runs crappy then you know is somewhere on the motor.

[garbubba]

Thanks for the input guys, I was thinking electrical since it came & went like somebody throwing a switch. I have a 6 gallon tank just filled up. & I'm on the hunt for a new bulb, hose & water seperator.

I'll let you know how it goes.

Doug

[garbubba]

It's embarrasing, but I just took the boat out again for the first time in 4 months. I could come up with a million excuses, but that wouldn't help.

Anyway, I had changed the water seperating filter, bulb & lines,and another filter that I had forgot about between the tank & water seperating filter that was nasty & gave me great hope that y'all were right & this would fix it.

She was a bit hard to start at first but then ran like a champ all the way out into the gulf & Horn Island. We decide to switch spots & shortly after there it goes, same as before, full power, then 1/3 of that, finally it stuck & stayed where the max RPM's were 2000. That made for a long ride home, but it could have been longer, right?

Fuel seems fine, I looked for loose wires & the like, nothing I could find.

It seems electrical, cuts in & out & won't idle, but I'm not sure.

Any ideas?

Doug

PS - wish I could afford a 150 yammy 4 stroke!

[willy]

Went thru the exact same thing with my merc 150, turned out the first time to be bad coils I believe then the second time the power pack I beleive it is called.
Whichever or whatever it is ignition related and an expensive pain in the balls to get diagnosed unless you go right to a good merc guy or you have the diagnostic skills. Apparently there are several causes in a mertc engine electrically that do the same exact thing

[macojoe]

Whichever or whatever it is ignition related and an expensive pain in the balls to get diagnosed unless............

Or you live next to BS :love:

The power packs on a Merc are called switch boxes. Thats as far as I go, I turn to the boartd and BS when crap hits the fan!!

Therm, spare, BS all will be by soon I am sure!

Good Luck

[garbubba]

it could be one power pack going out, that's what I thought when it first happened. It seems to happen with a warm engine more too (never has happened until it's run awhile).

Is this something I can test or should it go to the shop? I do have a pretty good dealer I've used a couple of times. I have a VOM & some skills in that area (jack of all trades, master of none!)

Doug

[macojoe]

Like willy said, its a easy fix, but you need to know what the reading's are to be, meaning you need the book and a meter.

If you have a guy you trust and can give you a good price then go to him.

Ask him to test and let you know, then you can look for the part yourself and change, it will be cheaper and its easy for you to do.

When I asked here about mine when it went I bought ione from ebay cheap and they were the same on each side, so I changed one and it was the same then I swapped it out for the other and it was good to go. n That was on a Evinrude, I hear its better to change both on a Merc??

[spareparts]

youre going to need a DVA meter to check the system out. Go to CDI and check out diagnostics http://cdielectronics.com/portals/0/downloads/Troubleshooting%20Guide%202006.pdf

they have the testing tools and parts, and yes, its better to replace both of the switch boxes at the same time