Hey Bigshrimpin!
 

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

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

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

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

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.

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.

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.

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

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!

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