Outboard Carburetors leaking fuel into intake

[Hofty]

1980 (to be verified) Mercury Black max 150hp. (S/N 5503928). Now I believe it is a 1980 but not entirely sure.

I have been having bogging issues on the lower end and had a shop check out the stator low/high which checks in spec. I am thinking the float needles are sticking. Thoughts from the video? Fuel gets wiped up and then accumulates within 10-30 seconds in the intake of carburetor.

Info: Carb part 1382-6425 s/n

Questions.
1. Based on the Serial number does anyone know the exact year and spec? See attached spec sheet
2. Is this fuel leak likely associated with a low end bug with float bowls? My understanding the float bowls effect idle and low end power but once main jet is used then there is no issue

 

[jimmbo]

"2. Is this fuel leak likely associated with a low end bug with float bowls? My understanding the float bowls effect idle and low end power but once main jet is used then there is no issue"

Low End Bug?
The Fuel Level in the Bowls affect every aspect of a Carburetor's Performace. If the Level is too high, the Main Circuit starts too soon, and if too low, the Main Circuit is delayed. Either Scenario can cause a Bog. Low level is usually a misadjusted Float or low Fuel Line Pressure, a high level can also be from that, but a heavy Float from Fuel Absorption, or too much Fuel Pressure
Bogging can also be caused by incorrect Sync between Spark Advance and Carb Opening.
How long have you owned this engine, and what is it's History, repairwise?

 

[Hofty]

I mean't low end bog.

I have owned the boat/motor for around 1 year. Initially the idle and the holeshot was fine. Then slowly it deteriorated. I have not fiddled with the sync or spark advance so most likely culprit is the float bowls not adjusting due to sticky needle? Repairwise I have kept up with all maintenance. Never taken the carbs off tho and the shop tested the electricals incl switch box, removed flywheel and checked the stator for appropriate voltages. All checks out.

 

[dingbat]

More than likely the flaot needles are leaking.
Pump primer bulb to “hard” and maintain pressure. Bulb should not leak down Or pump fuel into the throat of the carbs

 

[jimmbo]

How was the engine Winterized? There might be some Gum and Varnish gumming up some of the Carb Passages and Air Bleeds. Happens when Fuel sits a long time without being Stabilized.

 

[Hofty]

I put stabilizer in the fuel. I ran the boat every 2 weeks in the winter on the muffs for at least 7-10 mins. Religiously. There was no bog before when I purchased the boat. I am more and more inclined to think the issue is the stator/trigger, high vs low. I'm thinking if it bogs then there might also be perhaps a hole or perforation in the fuel line or a air leak in the fuel line. Then again I have not taken the carburetors off and done a deep clean. I opened up the float bowls and sprayed carb cleaner into them and thru the air bleeds. So I'm sort of stuck what to do.

 

[jimmbo]

I mean't low end bog.

Initially the idle and the holeshot was fine. Then slowly it deteriorated.

50 yrs ago we had a 40 HP that slowly got worse over the Summer. It was taken in for a tuneup, Spark Plugs, Points and Upper Crankshaft Seal. Was like a New Motor, for the first 10 minutes, then the Flywheel came off. Our engine had suffered with worn Points, and the resulting retarding of the Spark Timing. Your engine shouldn't suffer from that, unless the Linkage has somehow managed to Retard itself, or is not fully advancing