Down under rebuild of 90HP Force

[hundee r1]

Ok, so a few may have notice a few questions from the bloke from down under with the troublesome 90HP Force.

Bit of an oddball around these parts, so when coming across an issue, I post on I boats.

Like here:
http://forums.iboats.com/force-chrysler-outboards/do-i-need-prop-swap-my1994-90hp-force-594825.html

So with the comp readings down, I had no choice but to dive in and get dirty. But prior to turning any spanners a timing check was required.

Using this helpfull thread:
http://forums.iboats.com/force-chrysler-outboards/how-check-timing-force-125-a-594811.html


I didn’t spend too much time but at full throttle I was seeing between 32-34 degrees and between 8-10 at idle = too much I think but will re check it once finished. I did check the tacho reading with a snap one tool and can confirm that its reading correct and I indeed have been maxing the motor out at no more than 4100rpm.

Couple hrs after the first spanner is turned:

A bit latter:

The cause, 2 sets of smashed rings/pistons:

And I’m pretty sure the bearings shouldn’t be this colour:

I managed to pull the thing out and apart without having a stripped, broken or seized bolt, but I did manage to snap both of the crankshaft locating rings due to my haste and gorilla antics

Item 3 shown here:
http://www.**********/parts/search/Merc/Force/1992/H0906F92C/CRANKSHAFT AND PISTON/parts.html

So this is where I’m at, hoping you fellow Jedi’s can pass on any helpful tips on getting this thing back in tip top condition. Things like pitfalls for dumb players, a good place to source parts from that will ship to Australia and any other banter that may be helpful to my cause.

At this stage I m hoping these guys will help me out with supplies:
Powerhead Kit - complete rebuild kits for outboard motors

anybody used this place? I rang them last night and waiting on a confirmation of shipping costs and payment details, but I’m all ears if someone else has another supplier or past experience with this place. I spoke to George on the phone, and he seemed very good and Im waiting on the manager to return my email.
I have the option of 3 different pistons, WSM? Sport marine? And Wiseco forged
I spoke to a guy here in Australia that had a bad experience with forged Wiseco pistons on his 105 Chrysler, had a piston nip up and upon disassembly found out the piston was out of spec. In addition, the piston height was too low and thus had lower than normal comp. He rebuilt using Vertex pistons and is much happier.
Opinions on pistons? George also said no gains to be had by using the Wiseco but it was up to me.

Any other tips, opinions or views? Id Love to hear them!!

Thanx guys!!

 

[jerryjerry05]

Re: Down under rebuild of 90HP Force

Actually the bearing carrier is that color.
Never seen that site before. LOOKS GREAT!!!!
Prices and pieces???? Great!!!
Just make sure the replacement pistons can be bought oversized???
Does the cylinders need honing or boring?
Pics???
You might be one of the lucky ones and not need a bore job.
Ask FrankA about the pistons and what kind? The stock piston/wrist pin will need to be pressed in.

 

[hundee r1]

Re: Down under rebuild of 90HP Force

nah, 2off the bores need to be bored, so will do all 3. Wont do that till I have my pistons here tho.

Another good site which seems more automated is this one, prices arnt as nice, but still good tho:

OUTBOARDPARTS.COM CHRYSLER/ FORCE OUTBOARD MOTOR PARTS, SUPPLIES.

How did u go with the Sharks Jerry?

 

[jerryjerry05]

Re: Down under rebuild of 90HP Force

Were going out today.
Instead.
We went out on the Ft Pierce Lady.
Winds were up to 30+
7ft waves, out of 35 people on board 20 or more were chumming.
We should have stayed on the dock.
Were gonna try for sharks today. It's gonna blow again just hope it blows from the right direction???

 

[Frank Acampora]

Re: Down under rebuild of 90HP Force

Basically, try to use any brand forged pistons. I like Wiseco and contrary to some people, have never had an issue with them. But, buy whatever brand you are comfortable using.

DO NOT buy stock oversized pistons. These stock cast aluminum pistons with the semi-keystone top ring are more prone to breaking the top ring, just as your pistons did. I have a 150 that did 2 cylinders, a 90 that did one, a 120 that did 2, and a couple of other engines I worked for some other people---get the picture?

ALL aftermarket pistons are manufactured to precise overbore tolerances to meet clearance requirements in the cylinder. THUS: You measure (mike) the bore to decide what overbore you need (.010, .020, .030) and then buy the piston. If you have the machine shop bore and hone to an exact oversize (within normal machining tolerance), the piston WILL fit. No need to have the piston on hand. And, if you misread or for some reason found deeper damage and bored too little, you don't need to return a too small piston.

SO: Bore to oversize first, then buy the pistons. BUT: Remember that you are limited to .030 overbore MAXIMUM. Yeah, they do sell .040 over pistons but factory does not recommend going this far. Cylinder walls become too thin.

 

[hundee r1]

Re: Down under rebuild of 90HP Force

Cheers frank!! The guys at Tampa have come back to me with a quote to use 20thou Vertex. I'm comfortable ,should I be ?

 

[Frank Acampora]

Re: Down under rebuild of 90HP Force

Well, if they know what they are doing and if they have "miked" the bores then yes, you need to take them at their word.

I never used vertex but they are an old brand name that has been around for years in the auto high performance world. back in the day many dragsters used them. Once you get them let us know about your impression, how easily they were to install, and how the engine runs.

 

[hundee r1]

Re: Down under rebuild of 90HP Force

I havnt had the supplier "Mike" the bores, but Ive had a good look at the scouring and getting another opinion tonite from my local machine shop, but my gut feeling is that 20thou will clean up fine. The guys at Tampa did say that they can supply 30 thou, but rarely have to. Id rather keep it as small as possible in case it ever happens again at a latter stage.

I havnt heard a bad word about Vertex yet, they are a cast piston tho so comparing them to a forged Wiseco isnt really fair.
On a side note, have you also heard mixed result about Wiseco? cos until this research I just assumed they where an excellent brand. I guess even the best companies can have QC issues. Regardless, I have enough time to bore the block to suit the pistons supplied.

Dont worry, I intend on posting plenty of pix and Im sure many questions. If the thread helps one other person Il be a happy.

and on that Note, like I said I broke Item 3 shown here:
http://www.**********/parts/search/M...TON/parts.html

Powerheadkit.com are also able to supply them at a small cost, but how do I make sure I dont break them upon install? I tried taking them off the crank whilst the crank was still in the case and thus snapped. Im assuming the trick is to install them on the crank without the big end bearing installed and slip them on sideways? Obviously with the crank on the bench!!

 

[hundee r1]

Re: Down under rebuild of 90HP Force

guys, just occurred to me I should ask the below whilst I await delivery of my rebuild kit.

My stator, looks in great condition, except in a few spots the black goo has ozzed out and re solidified. Hard to explain without pix, but should I be looking at testing it some how or replacing it regardless?

Volt meter on the dash always read 12volts whilst motoring and tacho worked fine and accurately

 

[Frank Acampora]

Re: Down under rebuild of 90HP Force

Well, I can't access your site but I assume it is the crankshaft seals between cylinders that broke. With the crank out of the block, slip them over the bearing area. Then, spread them slightly and put into the groove in the seal area. Next, assemble the crank bearings. NOW, Carefully set the crank into its seat. Start with the top bearing and work down, seating each bearing on its pin. At this stage, be certain the crank seals are still in the grooves. When the crank bearings are all seated, rotate the seals so the open end is down in the block. Install pistons and rods. Install the front crankcase cover.

Even if Vertex are cast, they are a reputable piston manufacturer so I would not be uncomfortable.. As far as Wiseco, I have heard people saying that they have seen barrels full of bad ones taken from engines. As far as I am concerned, this is all hearsay, just like Ethanol will ruin your engine, Amsoil can be used at 200 to 1, Etc.

I have used Wiseco exclusively now for years and have yet to see a bad one. I use them because they are complete and are very easy to install.

I misunderstood your statement about .020 over. DO NOT take the distributor's word. They can not see and measure your engine bores. Take the block to the machine shop that will do the boring. Let them measure the bores and tell you what size piston to order.

Black "goo" from the stator means it has overheated and there is a good chance it is now bad. Measure the resistance of both capacitor charging windings. Measure the resistance of the battery charging windings. If any are not within tolerance, then replace the stator.

 

[hundee r1]

Re: Down under rebuild of 90HP Force

yep, crank shaft seals mate . Epic stuff Frank!!! very helpfull, and many thanx.

One other question in relation to the boring, should I be refering to piston suppliers or factory manual for piston to bore clearance. Im yet to see the pistons or the manual so cant say what the figures are at this stage, they may be the same?

 

[Frank Acampora]

Re: Down under rebuild of 90HP Force

I have said it any number of times: Pistons are manufactured to specific bore sizes and clearance is built-in. If the machine shop does a decent job boring the block to size, the pistons will fit with correct clearance.

That is why I say: " let the machine shop determine what size to bore to (.010, .020, .030) and then buy the pistons."

 

[hundee r1]

Re: Down under rebuild of 90HP Force

Wishing I had a happy update.

Got my parts delivered last Saturday, pretty disappointed to find they'd sent standard size pistons instead of the 20thou agreed/ordered.:grumpy::grumpy:
rang them first thing Monday, got apologies on the phone and "send them back , email us proof of the freight and we will send the right ones ASAP" so I did it straight away, that was over 4 days ago,another phone call from me and a couple emails and I still don't have a tracking number saying they've sent the right parts.
So Atm, I'm out of pocket $65 for the return freight and don't have any pistons.....not real happy

 

[hundee r1]

Re: Down under rebuild of 90HP Force

PAYPAL DISPUTE OPENED

 

[belairbrian]

Re: Down under rebuild of 90HP Force

Item 3 shown here:
http://www.**********/parts/search/Merc/Force/1992/H0906F92C/CRANKSHAFT AND PISTON/parts.html

Just wanted to pass along that when you insert a link with that website this site converts it to asterisks. your website had "boats" in it's name, correct?

 

[hundee r1]

Re: Down under rebuild of 90HP Force

yes^^^ correct. Intresting.

anyways, happy to report that after 6 weeks of placing my order I finally have all my bits!! I was reimbursed for my freight aswell, so all is well that ends well I guess and now time to get on with the rebuild.

I have 2 questions straight away that Im hoping will get clarification.

firstly, the roller pins in the big ends. Is there an easier way of assembling them appart from placing them in the rod end using assembly lube prior to dropping the crank in? seems real fiddly and I can see myself having to fish out every second pin as they fall into the case, and then what, place all the others in the cap end, trying to get them all to sit still as you bolt it all up? sheesh

secondly, So I have all of it together, but before a bolt up the crankcase I need to apply sealant to the mating faces, light smear over the whole face or just a continous strip , circling the thru bolts aswell?

Hope someone will help me, Im good at following instructions but dont really want to stuff this up.

was a long time ago, but I have put togther a couple 4 stroke car engines and in more recent times have rebuilt a few mazda rotary engines with great success so I am some what capable. hahahaha

 

[pnwboat]

Re: Down under rebuild of 90HP Force

I have 2 questions straight away that Im hoping will get clarification.

Firstly, the roller pins in the big ends, is there an easier way of assembling them appart from placing them in the rod end using assembly lube prior to dropping the crank in? seems real fiddly and I can see myself having to fish out every second pin as they fall into the case, and then what, place all the other half in the cap end, trying to get them all to sit still as you bolt it all up? sheesh I think everyone has their own specific technique. I just use some light automotive chassis grease to hold them in place. Only dis-advantage is that the grease usually ends up on the plugs (black residue) and you have to clean them off ofter you fire it up the first time.

secondly, So I have all of it together, but before a bolt up the crankcase I need to apply sealant to the mating face, light smear over the whole face or just a continous strip , circling the thru bolts aswell? I use a light coat of high quality silicone sealer over the mating surfaces. The two mating surfaces are machined for a very close fit. You only need enough sealant to seal any small irregularities between the two. Be sure to clean the mating surfaces thoroughly with some acetone or some other solvent before applying the sealant.

 

[hundee r1]

Re: Down under rebuild of 90HP Force

Thanx for the reply mate!! With my kit I got a tube of OMC assembly lube, Im assuming its used in a similair way to vaseline when I assemble my rotary motors. Will use this stuff to hold the pins in place. I can just see my fingers covered in the stuff and the pins sticking to my fingers haha. regardles, looks fiddly.

I aslo got genuine OMC sealant paste with the kit, I havnt looked in the tub but I assume its suitable for the crankcase.

Many thanx, and Im all ears for further tips, Il be sure to update with pix

 

[pnwboat]

Re: Down under rebuild of 90HP Force

It's not that hard to put the big end bearings in place. There several ways to do it. Here's one way. Install the piston and rod and position the rod close to the main journal. Just enough gap to be able to insert a single roller bearing. Use some of you goo to hold the bearing in place. Take the bearing cage and position it so that it's barely in contact with the single roller you inserted. Insert the next roller into the bearing cage and push it in. Just keep doing this until you've inserted all the bearing in the upper half. Bottom half bearing shell/rollers can be completely assembled and installed.

One other tip. Put a light chamfer the sharp edge of the exhaust and intake ports in the cylinder where the rings come into contact with the cylinder wall. Minimizes the chances of the sharp edge catching the piston ring. Double the oil (25:1 ratio) until the motor is broken in.

 

[jerryjerry05]

Re: Down under rebuild of 90HP Force

The assembly grease is the only thing to use.
It's designed to melt at a much lower temp than an axel grease.
You can actually cause premture failure with the other grease.
The spaghetti strip and a 1/16th in. strip of silicone is all that you need.
Sealer on the bearing surfaces too.
DON"T use a magnet on any of the bearings.

The tricky part, the locating pins on the main bearings.
They MUST fit before you install the intake manifold.
That's the hardest part.
I used a marker and indexed the holes 180d and marked the crank where the holes lined up.
It can be a hard job.
Any new bearings? Measure them,make sure they are the same size as the old.
I just did a rebuild and it went great.New piston and new rings and bearings for that cylinder.
Assembled and it was too tight???
Turns out the bearings were .001 over sized.Luckily I had a set that fit.
Even slightly it can cause the parts to be magnatized and attract shavings into the bearings.