'86 85hp Force low compression all 3 cylinders but runs

WildBill79

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I have 1986 85 hp Force that will start up first try every time and run in a bucket in neutral but when I put it in gear in the water it has a terrible bog and usually dies when I give it throttle. If I am slow with the throttle it will usually start going, get on plane, and do about 30mph. A compression test was performed and it said there was 60psi on 2 cylinders and about 70 on the other. I did the compression test on a cold motor and warm motor with and without the throttle open and got the same results. Does this seem right? Where should I start? Thanks
 

WildBill79

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Re: '86 85hp Force low compression all 3 cylinders but runs

I should also say that I have the Clymer manual and I am not affraid to get my hands dirty. I was thinking of looking at the head gasket first
 

WildBill79

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Re: '86 85hp Force low compression all 3 cylinders but runs

In neutral it will hit 5000 rpm no problem. In drive it really doesn't like to go more than 1000rpm, but has been known to get into the 4000s when the stars align
 

Frank Acampora

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Re: '86 85hp Force low compression all 3 cylinders but runs

60 and 70 psi is definitely low and in this case probably indicates worn rings and cylinders because all are essentially equal. However, it could be a head gasket or even loose head bolts so it pays to check them too.

As far as stalling, low compression can cause that but the most common cause is too low an idle speed and fouled spark plugs. The idle speed should be about 700-750 RPM in forward gear in the water. this usually translates to about 1000 RPM in neutral.

Bogging on acceleration is usually a carb problem. Clean the carbs and then do a synch as described in the sticky at the top of the page Chrysler and Force FAQs.
 

jerryjerry05

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Re: '86 85hp Force low compression all 3 cylinders but runs

Low compression could be the guage.My brothers reads 25#s different than mine.They all don't read the same.Get a different tester.
Poor performance could be the timing is off the fuel pump needs a diaphram.The carbs dirty.Water in the fuel.Do a spark test. Profile?? You might be close to someone who can help.J
 

WildBill79

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Re: '86 85hp Force low compression all 3 cylinders but runs

Profile has been updated

The head bolts were torqued to spec. A new fuel pump diaphragm was installed and new plugs. Idle speed is correct according to what Frank posted. I am going to try a different compression tester. I don't see how it would start on the first try every time, even cold, and run decent in neutral with only 60psi compression. I will also make an attempt at cleaning the carbs and doing the engine synch and see how that goes.
 

WildBill79

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Re: '86 85hp Force low compression all 3 cylinders but runs

I tried a different compression tester and got 120, 120, 118 on a cold motor so I guess that is good news. I will do it again on a warm motor after I get everything synched.

So far I have the three carbs opening to WOT at the same time and I adjusted the timing to 28 degrees while cranking the motor in gear at WOT. One problem I ran into after doing these adjustments is that in gear I can go to WOT smoothly on the controls but in neutral I can only go about half throttle before it binds. If I adjust on the linkage I can get neutral to go to WOT smoothly but only get to half throttle in gear so for now I settled for hald throttle in neutral and WOT in gear. Is this a problem? Anyone have any pointers on how to fix it. I have the Clymer manual but can't find where it shows how to adjust for this problem.

Next question, is the low speed needle mentioned in step 8 of Frank's synchronizing carb sticky the "idle mixture screw" referenced in the Clymer manual.
 

Justinde

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Re: '86 85hp Force low compression all 3 cylinders but runs

Just my 2 cents worth. I don't know why you would be concerned with an outboard that won't rev in neutral- I dont know why you would want to? Franks sync is the idle mixture screw/lowspeed needle is one in the same ( you should only have 1 anyways). Hope this helps, but I'd be happy with WOT in gear :)
 

WildBill79

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Re: '86 85hp Force low compression all 3 cylinders but runs

Not too concerned really, since I now have a smooth WOT in gear. I was more curious if this was how it was supposed to be, or if not, how do I fix it since I am already in there working on stuff. Thanks for the info on the idle mixture screw/lowspeed needle. I will get that adjusted tonight after work.
 

jkoppe73

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Re: '86 85hp Force low compression all 3 cylinders but runs

The shifter is not made to go to WOT in neutral, only about a quarter of the way, maybe a little more, just for a fast warm-up idle. On my 85 85 hp, in neutral, you pull out on the handle and move it forward for fast idle.
 

GoldLS1

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Re: '86 85hp Force low compression all 3 cylinders but runs

The shifter is not made to go to WOT in neutral, only about a quarter of the way, maybe a little more, just for a fast warm-up idle. On my 85 85 hp, in neutral, you pull out on the handle and move it forward for fast idle.

Mines the same way.... Only about 1800 rpm in neutral.
 

WildBill79

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Re: '86 85hp Force low compression all 3 cylinders but runs

The shifter is not made to go to WOT in neutral, only about a quarter of the way, maybe a little more, just for a fast warm-up idle. On my 85 85 hp, in neutral, you pull out on the handle and move it forward for fast idle.

Mines the same way.... Only about 1800 rpm in neutral.

Thanks for this info. For some reason before I got everything adjusted properly I could go to WOT in Neutral and in Gear. I kept hearing about fast idle but couldn't figure out what it was since mine went to WOT. After looking at the linkage I'm not sure how this was possible. I now feel good about the adjustments I made. I am going to fire it up tonight and finish my adjustments with the idle screws and hope this thing finally runs good.
 

WildBill79

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Re: '86 85hp Force low compression all 3 cylinders but runs

I fired it up last night and the motor sounds different. I guess in a good way. The tone of the exhaust is different from what I am used to hearing. It is now much smoother at idle almost instantly where before I had to let it warm up at a high RPM before I could bring to idle or it would die. The issue I have now is when I try to adjust the idle speed it doesn't change the RPM any, it sits at 1000 in neutral, and adjusting the low speed needles on the carbs doesn't really do anything unless I turn them all the way to lightly seated. Then RPM will pick up slightly. I returned the needles to 1 1/8 - 1 1/4 turns out. I think what I need now is a carb cleaning.
 

jerryjerry05

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Re: '86 85hp Force low compression all 3 cylinders but runs

The idle should be set ,warm,in gear and in the water.
The front screws should be turned in and then out 1 and 1/8th and left alone.
The idle is set on the towershaft.
If you've done the linc and sinc,It will allow you to adjust the idle.
Static timing? Got the FACTORY manual??? You really need that.J
 

WildBill79

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Re: '86 85hp Force low compression all 3 cylinders but runs

I have the front screws 1 1/4 to 1 1/8 turns out. The instructions say "from lightly seated" but it is difficult to tell in 1/8 turn increments how close I am from my definition of lightly seated, but it should be close.

I have been adjusting the idle from the tower shaft but it does not seem to do anything even though I see the throttle cam moving. I haven't been warming the motor up very much or putting it in gear so I will try that again this weekend when I put the boat in the water.

I have the clymer manual and I set the timing based on what it said. WOT, in gear, cranking motor set to 28 degrees. It also said I could set it to 30 degrees with the motor running in gear at WOT, but I haven't figured out a place where I could safely do that.

Overall I am happy with how it starts and runs in a bucket. The big test will be this weekend when I put it in the water.
 

WildBill79

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Re: '86 85hp Force low compression all 3 cylinders but runs

Before I put the boat in the water this weekend I replaced the headgasket since I had one at the house. The old gasket turned out to be good. All three pistons looked good and there was hardly any carbon buildup anywhere.
Yesterday, I was able to do a test run and overall I was happy, at least compared to how it used to run. Idle was good. WOT holeshot tests were good, but the biggest improvement is the motor will now start just by turning the key in neutral when it is warm. I used to always have to play with the choke and throttle to get it to start warm or cold. I also added come sound deadener to the inside of the outboard cover where there was previously nothing, so this added to my enjoyment.
There are a still a few more issues I want to clear up, but I will start a new post for those since my original problem on this post was solved.
 

bashr52

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Re: '86 85hp Force low compression all 3 cylinders but runs

What did you use as sound deadener? I need to do the same thing on mine......
 

jerryjerry05

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Re: '86 85hp Force low compression all 3 cylinders but runs

They sell sound deadner at most marine stores.The hoods used to have foam in them.Then the foam started to go south it ended up in the carbs and actually killed a few good motors by getting sucked into the reeds and causing piston failure.
Make sure that you have the covers on the carbs.If the deadner comes loose and covers a carb you might loosa a motor.
I just left mine alone after it came off.J
 

WildBill79

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Re: '86 85hp Force low compression all 3 cylinders but runs

What did you use as sound deadener? I need to do the same thing on mine......

Some people may not think it is a good idea, but I used peel & seal from lowes. It is basically a cheap version of dynamat that can be picked up at Lowes for $20. I cleaned the cover real good and used 3m adhesive spray before putting the peal & seal down.
 
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