1984 85 hp Force question ( or 2)

ok, I am stressing a little. I have a 84 Bayliner Capri with a 85 Force Outboard we have had the boat about two years. It runs allright but lately we have had problems starting it, it normally starts up good initially then once we run it awhile it takes a while to start again.But after about 10 minutes or so cranks right up.

I thought it might be a cracked hose so I replaced all hoses( gas & Vacumm) same thing kept happening. So we got a bright idea to take it to a boat mechanic and get all 3 carbs re-built, we spent 200 bucks ( along with a new stainless steel prop repair and a transom saver built) The short of it we spent 600 bucks for all that.

Well as you can imagine we are excited to get it to the water a test it, new prop, carb re-build it's gonna run great. we get to the water and it starts fine but when put it in gear and you give it the gas it dies!!! runs fine in idle and you can even reave it up in neutral and it runs fine but once it goes into gear it dies.

Well I took it back to the mechanic to fix it AGAIN. He comes back and tells me it looks like your motor is blown because the cylinders will not hold pressure. Now my first question is Does a cylinder hold pressure or once the cylinder dropped down or fires doesn't the pressure subside??? It shouldn't hold steady pressure right???

Well I tested it myself with a compression gauge( didn't have the capability to see if it help pressure or not!!!) The top cylinder hits about 120, the middle cylinder about 129 and the bottom cylinder about 119, 120. Is there a problem with the 10 pounds difference on the middle one???

Here is what I have been told, 10 pounds makes a BIG difference and it's probably a fuel or spark issue and has nothing to do with a motor blown, mechanic just doesn't want to deal with it and telling me it's blown it saves him the head-ache. Is this motor done?? Or should I take it to someone to re-build the carbs again?? Or just trash it and find another motor??? Thank you for your help I am at a crossroads

Re: 85 Force question ( or 2)

PROFILE!!You might be close to someone who can help.No it won't hold pressure.
#1 As the piston moves in and out the pressure builds and releases.On the up stroke.The pressure builds and after it fires it pushes the piston and then it releases after it hits the exhaust ports.
When a compression test is done.The tester reads repeat strokes of the high pressure.
10 pounds is not that bad.The tester should be left on for at least 8-10 revs.Take the other plugs out.
Don't know who the mechanics was but it sounds like he might not be the best/brightest or doesn't want to work on Forces.Don't go back there.
Are the plugs burning ok? Any rust or water or anything different on the plugs.
First,do a compression test again.Then a spark test.Use a gap checker.The spark should jump 7/16".
Rebuild the fuel pump.Water in the gas?Ethanol is a bugger.Mercurys Power Tune to remove some carbon.Use it,following directions.The carbs,reset the air screws.In till they just touch(GENTLY) then out 1 and 1/16th turn.
Maybe set the idle up, should be 750-800.
Do these things and come back.J

Re: 85 Force question ( or 2)

Thanks Jerry I think you responded earlier I will adjust the idle next, I'm researching the rebuilding of the fuel pump!!!

Re: 85 Force question ( or 2)

I agree with Jerry...doubt the motor is blown. Seems like an idle rpm issue or your plugs are a bit fouled and it is loading up which a slightly leaner idle mixture may help as Jerry mentioned. You might take the plugs out and inspect your spark / for fouling.