Another 85HP Force Problem

[harley151]

Hi Guys,<br />Im new to the forum and iv went through all the 85/125 force problems that are similar to mine but have not seen any post of people resolving this problem so I just wanted to get some thoughts.<br /><br />let me give you a little history on it first:<br />At the time of buying the boat from my boss it ran ok at idle and lower RPMS but would not hit top end. After a carb rebuild, new water pump, new fuel lines, filter, water seperator, impeller, exhaust boot, plugs, timing and reg maintenence. It ran great till the end of the summer. Then one day it would be fine for the first 10 mins and then would not open all the way w/o bogging down. After 3 carb rebuilds I finally found a pinhole in the bottom float. It now has the new float in and ran great for a few months.<br /><br />Now Im having a problem that I dont think is fuel problem. When I give it WOT it jumps up and you can hear it sound normal and then just before it plains it loses some power. it still runs good but its not getting full power. I can throttle back down and do it again and it will do the same thing. Iv had someone pump the primer bulb just to see but no worky. I also changed plugs, changed out a spark plug lead, cleaned all the contacts but none have worked. Compression is good, timing is good and everthing else seems to be functioning fine. Im outta ideas now.<br /><br />Thanks for any help guys!

 

[ODDD1]

Re: Another 85HP Force Problem

Harley, when you did the carbs, did you remove the brass inlet fittings from the carb body? have seen fuzz build up in there and cause such a prob... motor runs until the carb empties out and then falls off power.....

 

[harley151]

Re: Another 85HP Force Problem

ODD1, yeah sure did. I did a pretty thorough <br />job on the carbs (after the third time) and I did have garbage in there whick I think was from the insulation glued to the cover. But it has been removed and the carbs done since that time. It really sounds like an electrical problem when it loses power. Its very sudden and at the same time on every throttle. <br /><br />Thanks for the tip!!

 

[12Footer]

Re: Another 85HP Force Problem

It could be a spark advance issue, or linkage adjustment btween the carbs (sync problem). It sure is fun trying to check,much less adjust the timing on them at WOT underway, but you may have to.<br />So before going there, try riching the carbs 1/4turn, to be certain it isn't empty bowl syndrome.<br />Also, try looking at the engine running in total darkness...Look for leaky plug wires, plugs, CD and such. Thunderbolt ignition systems, adopted by the Force line from Merc, are hothothot, and can jump 1/2" from a plug wire.<br />Let us know what u find. maybee you got it nailed-down,maybee not.<br />

 

[ODDD1]

Re: Another 85HP Force Problem

well, harley...the weak spot in the igniyion system is those fine little trigger wires... from constant flexing the break right at the solder connection at the terminal bar....they will work at idle, but when throttle is advanced the wires twist and the connection fails....if you can, do a spark check cranking whithout distrubing any of the wires....then advance the throttle to maximum and try again....you might have spark on one cyl disappear....

 

[harley151]

Re: Another 85HP Force Problem

Thanks guys! 12Footer, just to be sure. Richer fuel mix would be a 1/4 turn out right? If so, I did try turning them out by 1/2 last WE just to see if I noticed any difference. No change though so i went back to 1 1/2 out. I will try it tonight in the dark and see if I can see anything shorting anywhere. Once again, thanks guys, this motor is really testing my patience.

 

[sony2001]

Re: Another 85HP Force Problem

Well if its a faulty CD causing it to run on two bangers there is a fourth connection on the CDs that can be used to replace the faulty one going to the third cylinder. Won't need to buy a new CD!