Help new 200 problem

[austen2019]

I’ve been posting about my merc 200 a lot lately. Been very helpful on this site with my issues. I finally took it out to the river and I had a problem. When loaded the boat wouldn’t take off almost like it’s super rich lots of smoke and after a little of not revving up it finally took off and did really well at the higher rpm’s. When me and my dad took it out it took off great and ram great until I came to a stop or slowed down it would idle really rough. We took it out a couple times with the same issue coming to a stop. But always took off really good. Loaded the boat up again and it did the same thing wouldn’t rev up and take off. This time I trimmed the motor up and it took off. The jets are all stock and I’m only at 500ft. Can the float be adjusted? Also the motor is about 2 inches to low, could that have caused the issue making it cavitate. Anyone else ever had this issue. Sorry for the long post 509802

[David - WI]

I would guess the exhaust is too deep in the water when the boat is loaded with the motor that low.

[Jim Speros]

Is the exhaust relief at base of cowl near the water line? I always suggested to me customers the trim the engine out while idling. Especially when relief is near waterline.

A couple other things to mention. well ask. What fuel are you running? That engine will appreciate premium. Fuel was better when engine was produced.
What rpm will engine run at wot with one person? And loaded up as you mentioned? I suggest you have a prop on it that will allow it to run near 6000 rpm light and at least 5600 loaded. If it is over propped running issue gets multiplied.

An over propped boat is adding load to engine. It can be related to pull off a light in second gear in a car.

If your sure your floats are acting correct and not allowing fuel into throat of carb while idling check your bleed hoses and check valves.

[austen2019]

It has 91 50:1 with quick silver oil. The prop is a 20 pitch aluminum and can’t go wot cause im breaking in lower unit. Im hoping raising motor will fix it but the smoke doesn’t make sense.

[OnPad]

Going to need more info for a accurate diagnosis.
Things to check is fouled spark plugs, spark jump test, timing on all cylinders, overflowing carbs, or a # of other things. Some troubleshooting on your end is going to be required, when engine acts up.

At what height is your engine mounted? How far is your propshaft below boat?

[rgsauger]

Everybody has given you some really good information here. I’m trying to remember, what year is your motor? 95? I’m also trying to remember how long it’s been since the carburetors were gone through. It is absolutely essential that the floats are set at proper height. Sounds like playing with the trim is helping for now. A lot of really good information has already been posted.

[austen2019]

I put brand new floats in the carbs but didn’t know they needed to be set I’m going to look at that and it’s an 84 mercury black max 200 2.4l with everything brand new pretty much.

[FUJIMO]

...eeeew ya. floats gotta be set. your on your way now...

[pcrussell50]

Yes ^^^

When floats aren’t set, you might get what I had here:

https://youtube.com/shorts/jNpViMKzr14?feature=share

It ran OK, but had poor idle and low power characteristics.

-Peter

[Jim Speros]

Its gonna run better with floats correctly set.

[austen2019]

510156UPDATE so set all the floats on the carbs which were not that far off. Raised the motor about 2in And sync all carbs and all we’re at 21 on the carb sync. Idles much better thank you for the help

[David - WI]

You really should go through the "link & sync" procedure to sync the throttle opening to the ignition advance... it's not enough to just sync the carbs like a motorcycle or snowmobile.

[austen2019]

So I did the lync and sync procedure the idle timing was at 4 and is suppose to be at 12 degrees and wot was at 14 and is suppose to be at 22 set all that correctly and it idles way way better. Thanks for the help