Process

Aggitated

Seaman
Joined
Apr 18, 2012
Messages
61
Well, due to process of elimination, I have narrowed mt 85' hp Forces misfiring problem down to one thing, seals. My question is how hard is it to replace the "Parting line seal" and the upper and lower crank seals?
 

jerryjerry05

Supreme Mariner
Joined
May 7, 2008
Messages
18,074
Re: Process

Not an easy job.
Gotta: pull the powerhead,remove the flywheel,spacer plate,all the electronics,crankshaft bearing cage and then.
The intake and carbs.
Linkage.
And probably a few steps I can't remember.


Now are you sure it needs those seals???
How did you come to that decision???
Lot's of work for a carb being out of adjustment(maybe)???
You check the reeds???
 

Aggitated

Seaman
Joined
Apr 18, 2012
Messages
61
Re: Process

Jerry, put boat in the water the other day and was able to get about half throttle out of her before she started cutting out. Then the bottom fell out before I had a chance to do or attempt anything. I'm not sold on the idea of seals being bad yet there is no oil at the top of the motor indicating a bad upper seal and I've sprayed carb cleaner with the motor running around the split in the middle and no change in rpms'. I've learned this motor well, and know every bolt and screw on it, and have no fear of pulling the powerhead off, again. (sigh) All bolts are super tight. Also, I put a timming light on each cyl. when missing, and no change in the light. If the electronics were breaking down wouldn't I be able to see it with a timming light? It never breaks, or shows a miss. I've done about all there is to do trying to eliminate the sputter nothing left but the seals. I didn't have time the other day to adjust carbs while in gear, thunderstorm ran me off the water. I'm going to take her back out later today and see what I can see. I've taken the reeds out twice, and had inspected by two different mechanics and according to them they are fine, all are closed and are working, gaskets look good as well. I would like to put a set of Boysen reeds in later on when I can afford them. Three months ago this motor was in bad shape. as soon as it went into gear it sputtered and wouldn't run one hundred rpms' over idle speed. At least I'm getting half throttle out of her now. There is good, better, best. I'm at the better stage now. I'm still not convinced the problem isn't still in the carbs somewhere. I've got to pop carbs off this a.m before I go, I set the floats up just a little bit to high the other day and she didn't like that at all..lol My motor is very senstive to any change just like a woman, oops I didn't just say that... I'll hit you back later this evening when I get back off the water.
 

jerryjerry05

Supreme Mariner
Joined
May 7, 2008
Messages
18,074
Re: Process

Any inline connectors(fuel line)?They sometimes leak and suck air.
Replace the fuel pump diaphram.
Replace all hoses.
Carbs,clean and make sure the jets are clear.
Water in the gas?Plugs burning right?
Compression test?
Don't bother with the reeds.Waste of $$$$
The fuel vent line clogged?Or the tank vent closed?
More discription what's happening?
 

Frank Acampora

Supreme Mariner
Joined
Jan 19, 2007
Messages
12,004
Re: Process

It is NOT parting line seals. If the crankcase was leaking, you would see gas and oil collecting on the block. The two halves of the crankase are machined to a close tolerance and the engine would most likely run well even if no sealer was used on the flanges.

Only half throttle? Check for a fuel delivery problem first then look at possible electrical.
 

Aggitated

Seaman
Joined
Apr 18, 2012
Messages
61
Re: Process

jerryjerry,
All fuel connections tight.
New fuel pump diaphram.
All hoses are new from tank to carbs with new clamps.
Carbs have been cleaned and are working as they should. (I think)
Gas tank has been dumped and I am using new gas, and a water seperator has been added, (new filter as well)
No 1 cyl. seems to be the problem child.
Pulled powerhead and replaced a bad exhaust gasket, (It was blown out)
Compression- around 118-120 on each cyl.
Fuel vent is open and working.
A new CDI stator has been installed.
I've gone over engine wiring harness with a magnifying glass literally. There are no breaks that I could see.
I've moved coils and CD modules around- with no change in th misfire.
As far as description, I left her on the trailer, throttled her up, and she started skipping at around 2000-2500 rpm. I don't have a tach so I'm just guessing. I've got a video of whats happening but haven't figured out how to insert yet. I'll work on that over the weekend. Opinions vary as to the problem.
Timming light showed no misfire when the engine was skipping. I would think that if this is an electrical problem it would be seen in a timing light.
Thanks jerry, I'll work on uploading the video.
Carbs have been cleaned twice. However, no kits have been installed.
Like I said, three months ago it missed as soon as it was put in gear, so I"ve made progress.
 

Aggitated

Seaman
Joined
Apr 18, 2012
Messages
61
Re: Process

Frank.
Yea, I sprayed carb-cleaner all down that flange the other day when I had her out and nothing changed, (I've sprayed carb cleaner at and around ever gasket with no change in the skip)
This has been a stumper of many local boat mechanics, some with over forty years experiance.
What about upper or lower seal?
Fuel system has been totally re-worked. New hoses, clamps, water seperator, fuel pump diaphram, etc...
Thanks for saving me from tearing motor down, not a plesant job.
New gaskets from reeds to carb.
Reved untill started bugging out, put timing light on each cyl. There was no skip in the light at any time.
Problem seems to be in No. 1
I've moved coils and CD trying to move the problem, but it stays the same.
Also, have ran at night under load, and there is no spark arching anywhere.
gone over engine wiring harness with a fine tooth comb, so to speak.
Done three compression test at different times each cyl. is at 118-120.
Should I pull the head and see what's goning on, expecially with no.1?
Thanks for your imput frank, you guys know this motor way more than I. I will listen.
I'm running out of options here.
I have not changed the trigger.


Would you sell me some bullets?
 

jerryjerry05

Supreme Mariner
Joined
May 7, 2008
Messages
18,074
Re: Process

If you have a timing light and it's not missing a beat.The trigger probably ain't bad.
You test all the cylinders? It might not be #1
Try changing coils?Grounds on all coils?
Sent U a PM.
 
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