0 compression on 85 force

[firstboat19]

Hi, I have an '85 85hp Force on my '85 1600 Capri Bayliner. I just bought it in June and struggled to start it up, then I realized the choke would get stuck every time I choke it, blocking air supply.<br />Anyway, the boat only goes around 5 mph tops!!! Sounds smooth, yet when I push it full throttle, it doesn't sound like it's making even 3,000 rpms!<br />The coils aren't in very great condition, but the engine doesn't skip a beat. The fuel pump would work fine even with closed gas tank w/ no ventilation.<br />Now the most important part. I checked cold compression and here are the results:<br />I - 105-115<br />II - 90-120<br />III - 0<br /><br />The third cylinder does move when starter is engaged. Friends tell me it's the reed valve. Could it be another problem? Or is it just reed? Also is it hard to replace reed? Any tips? Where could I find fairly-priced parts for my Force?<br />Also any other suggestions on how to restore power on my Bayliner?<br /><br />Thank You Very Much In Advance

 

[G DANE]

Re: 0 compression on 85 force

Hi Firstboat19<br /><br />When a tripple cylinder drops a cylinder you loose around 66 % of your power, the two others have to drive the dead cylinder. Normally broken reeds do not affect compression, unless they are pulled in cylinder and causes bad scooring and broken rings. First check if your reeds are ok, pull carbs and look through intake. If reeds are there, i would suspect a blown headgasket, not uncommon on this motor. Take a clouser look at the cylinder when you have head off. Get a manual first, earns its price manyfold.

 

[JB]

Re: 0 compression on 85 force

Yup, Firstboat. She's broke.<br /><br />But it isn't a reed. They do not affect cylinder compression.<br /><br />Broken rings, holed piston, severely scored cylinder wall or similar major mechanical failure is almost certain in #3. #2 may merely be carboned up. <br /><br />Force parts can be had from Mercury dealers, but I frankly don't consider your engine worth the cost of major repair. If it were a Merc, Yammy, OMC or other high quality engine it would probably be worth repairing.<br /><br />Pull the spark plugs from #2 and #3 (both are bad)and shine a light in to inspect for damage.<br /><br />You will get further advice from some who know Force engines better than I do.<br /><br />Good luck.

 

[boating brad]

Re: 0 compression on 85 force

yea jb is right, others may disagree but i say sell anything you can off it lower unit, coils, power pack, etc. go get a real motor! merc, yammy, johnson, evinrude, anything is better than a chrysler.

 

[Bco128]

Re: 0 compression on 85 force

I agree for the most part with G Dane and JB. Have had a similer problem. wont go into too many details exept to say i had to replace #2 piston.they dont run so well when there burnt i've noticed.anyway good luck to you and remember if you do need to replace a piston be sure you look at the walls closely for scoring, and be sure you deglaze them if thy are ok.new pistons will generally have a lower compression than old pistons with new rings.just as a point of info.I run an 86' force 85hp.the piston ran about $90.00 and rings were about $16.00 a set.Head gasket is around $7.00. As far as not worth repairing....I'ts a personal decision...but overall although the parts may cost more at times it is normally easier to repair a force than most of the high spec outboards. less of the worthless electronic junk on them to cause problems.

 

[firstboat19]

Re: 0 compression on 85 force

Bco128, is it hard/complicated to replace a cylinder (I've never got inside any engine yet, but I do have mechanical skills and plenty of common sense)? Those parts that you've listed, is that all I need? I have Clymer's manual, do you think that would give me enough knowledge to repair the engine myself? Also, what's deglazing?<br /><br />I thank deeply all members who have responded to my problem<br /><br />NiK

 

[firstboat19]

Re: 0 compression on 85 force

Also how to tell whether the walls are bad...just look for dents/scrathes/uneven surfaces or is there another way?<br /><br />Thanx

 

[firstboat19]

Re: 0 compression on 85 force

One more thing...is it OK for me to use the boat as it is right now for the rest of the season, or will it hurt it?

 

[wileecoyote985]

Re: 0 compression on 85 force

firstboat;<br /><br />I wouldn't keep running it if you have any plans to possibly overhaul it. Doing so will almost certainly cause further damage.<br /><br />wile e