'98 Merc 200 v6 bulb not hard and labors under load

[aquasport1998]

Hey guys. I have a '98 Merc 200 saltwater that is having a couple of issues this season. Getting her ready this year, noticed that I had a fuel leak at one of the connectors in the motor. Tightened the compression fitting and it closed the leak up. Ran fine for the first couple of times out, then started laboring at around 3500 rpm, wouldn't get on plane unless I moved passengers to front of boat. (Didn't tell my sister that she had packed on a few pounds...didn't feel like swimming that day).
Noticed that bulb was not firming up when I primed, but motor would start. Replaced the bulb and the inline fuel filter. Also noticed a crack in the fuel line running to the bulb, so trimmed it and reinstalled the bulb.
Same problem. bulb doesn't get hard, but motor will start. Runs fine on muffs and in N at the dock. When I pull away from dock and try to get her up to speed, she does well up to about 2000 rpm now. Then labors hard and wont climb above that. In N she revs up to above 3500 rpm before I back her down ( I know not to do that often).

Wondering if I should replace the fuel line and the fuel/water separator. Any thing else to think about before I take her to the Mechanic. Carbs were cleaned 2 years ago. Read somewhere that it might be a power pack issue. How to test?

Thanks ahead for any help.

 

[BatDaddy1887]

Re: '98 Merc 200 v6 bulb not hard and labors under load

Usually, this is indicative of dirty carbs, or the fuel-pump needs a re-build, old fuel lines sucking air, clogged in-line filter, bad gas, etc. Try a whole can of Seafoam to start off with, that'll clean the system some. Also, try running the boat on a portable gas tank....that may isolate the problem.

 

[aquasport1998]

Re: '98 Merc 200 v6 bulb not hard and labors under load

Thanks BatDaddy. Will try the seafoam and the portable gas tank. Hate to be stupid...but....should i put the seafoam in the portable gas tank or in the regular tank?

 

[Coloradolakeboy]

Re: '98 Merc 200 v6 bulb not hard and labors under load

I'm not sure about the seafoam, but I would replace the fuel lines. Here is the link to the CDI ignition troubleshooting site.
http://issuu.com/cdielectronics/doc...t.xml&backgroundColor=000000&showFlipBtn=true

 

[j_martin]

Re: '98 Merc 200 v6 bulb not hard and labors under load

If the bulb won't harden up, something is wrong.

Look carefully down the throats of the carbs when you squeeze the bulb. If no overflow is occurring, then somethings wrong with the bulb or the lines to it. If it's flooding, well there's your problem. A white knuckle grip on the bulb will flood any carb, so be reasonable with your expectations.

Does any fuel sp

 

[aquasport1998]

Re: '98 Merc 200 v6 bulb not hard and labors under load

Okay, it doesn't rain for months...now when I need to work on the boat and put her in the water to test....rain, rain, rain. So, I'm trying to line up what I will try when I get a chance and in what order.
1. Test as J-Martin said: look at carbs when bulb is squeezed.
2. Seafoam in gas (should it be in the regular gas tank or in the portable in #4)
3. Run on portable gas tank to see if there is an issue with fuel lines and/or gas from installed tank.
4. Replace fuel/water separator.

Questions: J-Martin: When I am looking at the carbs...I've taken the air intake cover off, do I need to do anything to the carbs to check for overflow/flooding. I have done that, carb flaps (not sure what exactly to call them) were closed. Did not appear or sound as though there was much fuel entering the carbs (assuming I was looking at the right thing and did not need to have the throttle open.

Colorado: Thanks for the link. Not sure what you wanted me to notice or be aware of in the bulletin. Are you thinking that I may not be getting spark on some of the cylinders?

One more thing...the motor has been hard to start since I purchased it 3 years ago. After priming the bulb and pumping the throttle in neutral, I usually have to have it at 1/2 to 3/4 for the motor to start. Once it starts, its good to go. Does that change the recommendations?

Thanks for the help guys.

 

[Coloradolakeboy]

Re: '98 Merc 200 v6 bulb not hard and labors under load

1. Colorado: Thanks for the link. Not sure what you wanted me to notice or be aware of in the bulletin. Are you thinking that I may not be getting spark on some of the cylinders? .

Ran fine for the first couple of times out, then started laboring at around 3500 rpm, wouldn't get on plane unless I moved passengers to front of boat. Runs fine on muffs and in N at the dock. When I pull away from dock and try to get her up to speed, she does well up to about 2000 rpm now. Then labors hard and wont climb above that.
.

You may not be getting a strong enough spark to get the motor to go over 2000 rpm.
Go back to the link I posted and read the section on page 84 titled "Will not accelerate beyond 3000 rpm" and run the diagnostics. I had the exact same problem and was able to isolate the bad part.




As far as the hard starting, check the linkage to see if the carbs close when you give it choke. Do you get alot of smoke when it finally fires? My 175 likes to be at level to slightly pulled down when started and I hold the key in until it fires. I read the slightly pulled down allows fuel to go toward the back of the motor.

Read this link. How to test a boats fuel system.
http://forums.iboats.com/showthread.php?t=283363

You might have several issues to repair like I did.

 

[j_martin]

Re: '98 Merc 200 v6 bulb not hard and labors under load

Any flooding would occur before the throttle plates.

There's something wrong with the primer bulb or fuel line. Replace them.

Sounds like you don't know how to start it. Pumping the throttle won't do anything because it doesn't have any accelerator pumps on it. There should be a switch on the key that activates a solenoid valve (enricher valve) that dumps fuel into the bottom two carbs from the top carb float chamber before you crank, and into all 3 carbs when the engine is cranking. It is activated by depressing the key.

My normal procedure is.
1. Prime till the bulb is hard (before launch)
2. Throttle lever up 1/2
3. Turn key to run, depress for 5 - 10 seconds (longer in colder weather)
4. With key still depressed, turn to start.
5. Expect it to roar into life within 2 seconds.

 

[aquasport1998]

Re: '98 Merc 200 v6 bulb not hard and labors under load

Thanks for the suggestions, guys.

J-Martin, you hit the nail on the head. Replaced the fuel line (bulb was already new). For good measure I replaced the fuel/water separator filter. Put her in the water and she did great. Planes out and runs smooth. J-Martin, I didn't realize just how hard she had become to start. Your procedure was right on the money. She roared to life (and since it is a Mercury, I do mean roared.) Idled better and had good acceleration.

Will run the seafoam through for good measure.

Thanks, again for the help guys.
Happy and safe boating.

 

[KermieB]

Re: '98 Merc 200 v6 bulb not hard and labors under load

Ok, I'm seeing something new here... explain the "depress the key" step. I've never seen nor known of this. Would I have this on a 96 Maxum with a 150 Mercury ob. I just bought my first OB and am trying to get it started for the first time. (See "96 Mercury coming out of winterization" thread)

 

[j_martin]

Re: '98 Merc 200 v6 bulb not hard and labors under load

Nothing new, mercury's been doing it for at least 25 years. When you press the key switch in and it's on or in start, it operates the choke or enricher, depending on the engine.

It's in the operators manual and also in the service manual for your engine. Perhaps if you are going to own this fine machine, you should get the appropriate manuals for it so you know how to care for it and use it properly.

 

[j_martin]

Re: '98 Merc 200 v6 bulb not hard and labors under load

Thanks for the suggestions, guys.

J-Martin, you hit the nail on the head. Replaced the fuel line (bulb was already new). For good measure I replaced the fuel/water separator filter. Put her in the water and she did great. Planes out and runs smooth. J-Martin, I didn't realize just how hard she had become to start. Your procedure was right on the money. She roared to life (and since it is a Mercury, I do mean roared.) Idled better and had good acceleration.

Will run the seafoam through for good measure.

Thanks, again for the help guys.
Happy and safe boating.

Carry on sailor, enjoy your boat.