1988 Force 85HP Won?t Get up to Speed

Jimmog

Cadet
Joined
Jun 25, 2013
Messages
15
Hello: First time Poster here but have been able to keep my Motor running good for past 3 years because of advice and suggestions from different members?Thanks
I have a 1988 Force 85hp ? Model 856X8A- on a 17ft Bayliner Capri. A few weeks ago the motor started surging the odd time between half and full throttle. Problem seemed to go away then all of a sudden the boat would get up to a certain point then would not have enough power to get it up onto plane. The engine starts good, idles good and runs great in the lower speed range. Engine does not stall out at half speed just seems to run smooth but no top end speed.
Compression is 125-120-and 125 on bottom cylinder. Strong spark on #1 and #2 cylinder but very weak spark on #3. Plugs 1 & 2 had normal looking carbon build up and #3 was clean and shiny. Replaced plugs, new fuel pump diaphragm and new fuel lines. No change at all. From what I have read on the forums would it be ok to switch wires to the unused section of CDI pack #2 or would there be other options that I should try first. Thanks in advance.
p.s. My grandkids are coming up tomorrow and I was wondering if I would be causing further damage to the motor if I were to slowly take them ? mile over to their favourite crappie spot.
 

jerryjerry05

Supreme Mariner
Joined
May 7, 2008
Messages
17,923
Shiny plug is usually a no fire situation.
Check the trigger leads where they connect at the buss bar.

Sometimes the wire breaks under the shrink wrap.
No it probably won't hurt to idle or run slow to the favorite spot.
 

Jimmog

Cadet
Joined
Jun 25, 2013
Messages
15
Thanks for the quick replies. Will get on this tomorrow (fishing today) and will post results.
 

Jimmog

Cadet
Joined
Jun 25, 2013
Messages
15
Had crappy weather over the weekend so was unable to work on the boat. Heading North for our annual Moose hunt and will post results when I get back in a week or so.
 

jerryjerry05

Supreme Mariner
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May 7, 2008
Messages
17,923
Cool!! Good luck. PM me and I'll send my address so you can ship me some moose steaks. YUMM
 

Jimmog

Cadet
Joined
Jun 25, 2013
Messages
15
Back from successful Moose hunt (850lb Cow) Worked on boat and did the following: Checked all wires at Buss bar - OK Switched Lines on the 2nd CD pack - Still weak spark on #3 cylinder Swapped coil #3 to #2 and weak spark followed Installed new coil on #3 and now have good spark on all cylinders Took boat out but problem remains (wont get past 1/2 speed) I am now thinking of pulling boat out for winter and doing a rebuild on #3 carb. Is there anything else I should be checking? I did notice that the Jet (#24 on carb pics) was plugged pretty good when I tried to blow air through it, can this just be unscrewed and cleaned or should I wait until I attempt the carb rebuild? Please bear in mind that until I started reading this forum 3 years ago the only thing I knew about boats and engines was key-on key-off. Thanks.
 

Frank Acampora

Supreme Mariner
Joined
Jan 19, 2007
Messages
12,004
If the jet was clogged and the engine was run at full throttle or very near to full throttle, you had best do a compression check on all cylinders.Yes, the jet can be unscrewed and cleaned but it is not necessary. You can run WD40 and a pipe cleaner through it in place. No need to even remove the carb. BUT--- If the jet was clogged that badly, then the rest of the carb most likely is not any better. Best to remove all carbs and do a thorough cleaning.

Back to plugged jets. A partially clogged high speed jet will cause that cylinder to run lean at full throttle. The other two pistons will carry the poorly running one. This will result in detonation and a damaged piston. THUS: the need to check compression ratio.
 

Jimmog

Cadet
Joined
Jun 25, 2013
Messages
15
OK Thanks Frank. I will be pulling the boat out tomorrow and will do a compression test. If compression is still good I will remove all carbs and clean or rebuild them over the winter. I'll post results of compression test.
 

Jimmog

Cadet
Joined
Jun 25, 2013
Messages
15
Checked compression today 125-120-125 Good spark on all cylinders Boat out for winter now, will rebuild/clean carbs. Will let u know in Spring when boat is up and running. Thanks to everyone for advice and suggestions.
 

S.A. Baker

Petty Officer 1st Class
Joined
Aug 9, 2015
Messages
227
Geez....we don 't pull the boats out until the water gets stiff . It 's just the beginning of October ! Have been known to do a little ice breaking....but it's hell on wood boats! Learned that lesson one fall trapping! Almost had a long around the lake walk home !
 

jerryjerry05

Supreme Mariner
Joined
May 7, 2008
Messages
17,923
Old1 he said he pulled the boat for the winter.
If you have a problem post it and maybe someone can answer​?
Oh yea Welcome.
 

Jimmog

Cadet
Joined
Jun 25, 2013
Messages
15
Many thanks for the advice received...I replaced all spade connectors at the bus bar, pulled the carbs and cleaned them....Took it to the river and it is running like a new motor....Once again Thanks, you guys are Great!!!!
 
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