No power under load

[Elkgabe]

I have a 1971 Mercury 800 thunderbolt 4 cylinder outboard I am working on.
The problem: Will idle and increase in RPMS in neutral, bogs down and will not go over 5 mph in gear.
What I have done so far: New key switch, Wiring harness, CDI switchbox, coil, carbs removed and cleaned, high altitude jets,plugs,new floats. Compression: 125,125,130,120.
when I began the repairs I found vacuum hose from the bottom cylinder to the carb disconnected. Reconnecting did not make any change to lack of power. The boat did set for 7 years prior to me working on it. Different fuel tank and fuel. Have been running Johnson 7.5 horse on same fuel tank with no issues. I did bring the boat to a repairmen who after 300 dollars said it would have more power, but would need a distributor. Ohh he had said he cleaned the carbs, which obviously had not been a thorough job. When I pulled the carbs after, I found sludge in the filter above the bottom float and the float was cracked.

I have money invested and would love to get her running well.
Any help, much appreciated

 

[racerone]

A picture of that " vacuum " hose ?------Have you tried opening low speed mixture screws to see if it works better ?

 

[Elkgabe]

Here is a pic of the hose I refrenced. Will also post a pic of the distributor. Notice the spring, I wonder if this should be thereAlso i did adjust the low speed screws, I infer these are the carb idle screws? This had no affect on power under load.

 

[Elkgabe]

Today I was able to check spark on all cylinders. The connector that hooks to the the plug boots were not snug on any cylinder especially the boot to the fourth cylinder which idled rough with the in line spark light. I will replace all the connectors in the boots, although it doesn’t seem likely that this would be the sole issue.