85 HP force motor. 2 questions!

WhiskeyNoise85

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Dec 28, 2021
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Hello again everyone. Ya boy whiskey needs some helps from the pros again! First off OMG do this motor usually drink a TON of gas??? I mean no exaggeration about 1/2 a gallon a mile at 10-11 mph. (The motor it on a 21 ft pontoon)
Sorry this is gonna be a pretty long post but here goes. I'm a pretty good mechanic and I can do just about anything amd diagnosis anything but this motor has me stumped. 1986 85 hp force so when I go about half throttle it comes up to rpm and will run About 7..8 mph all day. But falls of its face in a bog if I go a hair more with the throttle...sometimes I can giggle amd wiggle it up to about 3/4 of WOT (about 10 mph). But if bogs anything after 3/4 now. And i know its a pontoon its not suppoused to be fast but its not right....ya know? I should have WOT.
So, I did a full carb clean,new primer ball, checked gas tank vent.And lines Replaced the diaphragm thing on the motor. New plugs.set the fuel idle mix screw to 1 turn out(bc that's where the Manuel says to start) Had a buddy drive and brought it up to its half throttle speed and pumped the ball and nothing happened. The ball wasn't "HARD" and it wasn't collapsed.
Now check this out . I could reach the butterfly control rod so I twisted them to WOT and VROOOM 16 17 MPH!!!
so please help me understand this if you could.
Ohhh. One other thing I checked the spark plugs last night and one was like super clean. Like brand new and had some oil on it...Pic on thread.20230529_010315.jpg
 

Nordin

Commander
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Jun 12, 2010
Messages
2,438
Check the remote control cables for right adjustment.
If you could open up the throttles more by hand the remote control need adjustment.
Clean spark plug.... check head gasket, exhaust cover gaskets (be careful if you suppose to remove the screws holding the cover).
Check the reed valves, later reed valves made of some plastic material often brakes.
Even the old stainless steel reeds can fail after a long time.
 

jimmbo

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May 24, 2004
Messages
12,961
Fuel Economy, 2 mpg, sounds quite Reasonable.
You can't treat/adjust this thing like you do a Car/Truck engine. There is no Idle Timing spec, as Spark Timing is what determines the Idle Speed. The Carbs are fully Closed at Idle, and will remain so for quite awhile as the engine speeds up. With the Exception of the Primary Pickup Timing, the Carbs only start opening after Full Timing Advance happens. Setting the Carb and Timing interaction is called a Link and Sync, and needs to be done according to the Factory Procedure.
 

jerryjerry05

Supreme Mariner
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May 7, 2008
Messages
17,927
You check the rpm's at wide open?
The wrong prop will kill ya at the gas pump.
The wrong pitch will cause excessive fuel use and bad performance.
I had twin 88/85's with 17p and got 3.2- 3.5 mpg.
I wanted MORE!!! speed. Changed to 19p props and got more.
2-3 mph. and about 20-25% more fuel usage
 

WhiskeyNoise85

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Dec 28, 2021
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Fuel Economy, 2 mpg, sounds quite Reasonable.
You can't treat/adjust this thing like you do a Car/Truck engine. There is no Idle Timing spec, as Spark Timing is what determines the Idle Speed. The Carbs are fully Closed at Idle, and will remain so for quite awhile as the engine speeds up. With the Exception of the Primary Pickup Timing, the Carbs only start opening after Full Timing Advance happens. Setting the Carb and Timing interaction is called a Link and Sync, and needs to be done according to the Factory Procedure.
Noooo that 1/2 half a gallon a mile sir.
 

WhiskeyNoise85

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Joined
Dec 28, 2021
Messages
47
Check the remote control cables for right adjustment.
If you could open up the throttles more by hand the remote control need adjustment.
Clean spark plug.... check head gasket, exhaust cover gaskets (be careful if you suppose to remove the screws holding the cover).
Check the reed valves, later reed valves made of some plastic material often brakes.
Even the old stainless steel reeds can fail after a long time.
Well what I mean by that is if I open the butterfly by hand I can achieve WOT. But I can also open then with the hand control...but I get bog. I'm going out there this after noon at 5 I will post a reply video.
ALSO I do have a hole in my exhaust boot for sure! Could this be causing the problem?
And I will check Reed valves later also. Thank you all for the rplys.
 

WhiskeyNoise85

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Joined
Dec 28, 2021
Messages
47
You check the rpm's at wide open?
The wrong prop will kill ya at the gas pump.
The wrong pitch will cause excessive fuel use and bad performance.
I had twin 88/85's with 17p and got 3.2- 3.5 mpg.
I wanted MORE!!! speed. Changed to 19p props and got more.
2-3 mph. and about 20-25% more fuel usage
i do not have a rpm gauge.
 

Nordin

Commander
Joined
Jun 12, 2010
Messages
2,438
If you have a hole/leakage in the rubber boot where some exhaust and cooling water exit at the back of the midleg cover the engine will breathe exhaust with the cowl on.
Try to run without the cowl and check if it perform better.
 

WhiskeyNoise85

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Dec 28, 2021
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If you have a hole/leakage in the rubber boot where some exhaust and cooling water exit at the back of the midleg cover the engine will breathe exhaust with the cowl on.
Try to run without the cowl and check if it perform better.
Ok yes o have ran it with cowl off the past 3 times I've been out to diagnosis amd fix it. Same problem. I will be at dock soon to take pics and vidoes. Thanks again for all the reply well get it fixed!!!
 

WhiskeyNoise85

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Dec 28, 2021
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Ok so update.. not getting fire to #1 sparkplug. ordering mudule.checked coil by switching wires and coil is fine.
 

Nordin

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Jun 12, 2010
Messages
2,438
Are really sure it is the CD module that is bad?
Check the triggers before you buy a new CD module.
You can use a regular VOM if you do not have a DVA meter.
But a DVA meter or DVA adapter is best.
The triggers should put out 0,5V or more and the resistance for the triggers should read 48-50 Ohm.
 

WhiskeyNoise85

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Dec 28, 2021
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47
I'll definitely check that bc the module is stupid expensive! 400 something thank you nordin!
 

WhiskeyNoise85

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Dec 28, 2021
Messages
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Screenshot_20230530_233336_Messenger.jpgquestion this mod runs num 1 and 2 cylinder. Would the trigger be bad of.the num. 2 cylinder is.still working? Probably a dumb question... also ignore that the highlighted wire is supposed to.go to cylinder. 1 not the wire that's in it...
 

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Nordin

Commander
Joined
Jun 12, 2010
Messages
2,438
Yes, the CD module has two channels and one can be bad.
you can swap the CD modules and see if the issue follows or not.
 

WhiskeyNoise85

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Dec 28, 2021
Messages
47
Sorry for the SUPER late up update.received_131403553319135.jpeg but after all that checking and trouble shooting.it all came down to a broken ground connector on this piece the green one on top looks like its on there. But the male tab was actually broken.thank all tou guys for the responses.shes running like a top again.20230612_105507.jpg
 
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