Johnson 150 Rebuild/Remanufacture Guidance

[Lectro88]

Take a green scotbrite or dishwashing pad and cut into strip wide enough to fit journal and polish. Wont hurt anything if you leave em alone either.

**Wont hurt anything if you leave em alone either.** agree with this..

my crank was a mild chocolate color also (But Smooth.!)
Leaving it alone..

the sanding with fine is ok... but you need to get all abrasion debris out of journal lube holes and hiding spots. (most cant do that properly)
so to me the reward for not scored surface is not worth introduction of grit in the mix of a rebuild.

nothing wrong doing this just care needs to be taken.
but me personally if not scored wouldn't mess with it.
now if we were talking rings and pistons seating... yes cross hatch. as mentioned.(for sure)
220 not gritty enough to cause severe damage if not cleaned and removed, but on rebuild I am trying to keep foreign debris out.
just my .02 cents

everyone that has replied thus far has given good advise and knows their stuff.

 

[Terrapin]

Does the same hold true for the connecting rod big ends, or do you definitely leave them alone? Inspecting my connecting rod big ends, they seem to have even less discoloration than the crankshaft journals.

 

[Lectro88]

Does the same hold true for the connecting rod big ends, or do you definitely leave them alone? Inspecting my connecting rod big ends, they seem to have even less discoloration than the crankshaft journals.

my stance would be the same. here too.
(kinda like if it ain't broke don't try to fix it)
this motor is made like a Giant chainsaw(kinda)journals are on roller bearings, mains are too.

with no scoring, its already a smooth surface. you are not trying to seal like compression in cylinder.
the point of attention is getting rod caps/rods perfectly aligned on re-assembly. Pay Attention to this.
put 1 together not on crank, slide bearing assembly in with fingernail amount of misalignment, now rotate bearing back and forth and notice hang up. (you don't want that in a rebuild)they make a $600 tool for that.
Any mis-alignment here will tell on you quick.

 

[ct1762@gmail.com]

my stance would be the same. here too.
(kinda like if it ain't broke don't try to fix it)
this motor is made like a Giant chainsaw(kinda)journals are on roller bearings, mains are too.

with no scoring, its already a smooth surface. you are not trying to seal like compression in cylinder.
the point of attention is getting rod caps/rods perfectly aligned on re-assembly. Pay Attention to this.
put 1 together not on crank, slide bearing assembly in with fingernail amount of misalignment, now rotate bearing back and forth and notice hang up. (you don't want that in a rebuild)they make a $600 tool for that.
Any mis-alignment here will tell on you quick.

i used faztbullet's recommendaton and did a light pass with 250 grit or thereabouts on the rod big and little ends with a dremel tool and those poofy abrasive things. made a nice frosty appearance for the rollers to roll and naturally polish it up, i'm thinking. before that, i always left them alone. i use the rod cap alignment tool: my favorite thing to do in the whole process. takes minutes to do once you get the hang of it, and always comes out perfect. of course, make sure not to use the tool on hand-sanded rods... precision ground only! lots of guys claim they don't use the tool with the newer precision ground rods, but i don't see how thats possible as the caps "spring" out, and without the tool theres no way to "push" them back in unless you find 1 rod in 10 that lines up perfectly.

 

[racerone]

Have not seen the need to invest in that tool.----Do rollers and crankshaft touch at full throttle ?-----Do rollers and bore of the rod touch at full throttle ?

 

[Faztbullet]

I have built many precision without it (guide)

 

[racerone]

If you were doing 2 motors a day then maybe the tool would pay for itself at $100 / hr.----Old tyme work methods are good enough for me.----Never had a rod damaged!!

 

[ct1762@gmail.com]

If you were doing 2 motors a day then maybe the tool would pay for itself at $100 / hr.----Old tyme work methods are good enough for me.----Never had a rod damaged!!

i hear you... the warnings in the manual always scare me talking about not using the tool. Plus, i can never get all of them lined up to were I'm confident. every time i use the tool, they align perfectly, and it doesnt take me an hour for the job. Clearly, im not patient enough but as I said how can you align them when the caps are sprung out? even when the cap is aligned perfectly center, you can feel a lip on both sides on many of these rods. do you just get a new rod? if that's the case, might as well save $ and just buy the tool.

 

[ct1762@gmail.com]

Have not seen the need to invest in that tool.----Do rollers and crankshaft touch at full throttle ?-----Do rollers and bore of the rod touch at full throttle ?

you are saying the rollers do not touch anything at full throttle? would explain why a couple motors i've built with the caps causing a ridge on both sides haven't failed.

 

[racerone]

The way oil or other lubricants like water ---" work " ---in bearings is not well understood.

 

[Terrapin]

Faztbullet, Thanks for suggesting Jay's Block Shop and giving me the contact information. Jason, did a great job on my block and was able to clean it up going .020" oversize. Jason fixed me up with WSM pistons, gaskets and seals. Jason is great to work with and I told him I got his name from Faztbullet on the iBoats forum.
I'm back on this project now and appreciate the tips on the connecting rod caps. In addition to the finger nail test, I plan on measuring the rod and cap side with a micrometer to confirm I'm not in a sprung condition when I snug the caps up prior to torqueing.
All the crankshaft journals and bearing surfaces are within the Johnson service manual specifications. However, three of the sealing rings were worn below the .154 minimum thickness and I will replace them.

 

[racerone]

I chamfer / break the outside edges of sealing rings.-----The sharp edge on them interference with movement as block changes temperature.

 

[Terrapin]

OK, I'll break the outside edges with a medium India stone. Is that acceptable, or do you have a better process?

 

[Terrapin]

I ordered OMC Gasket Sealant online, but received Loctite Aviation Gasket Sealant p/n 1525607. Is this an acceptable/recommended equivalent?

 

[Faztbullet]

Same thing in different can....

 

[Terrapin]

Question, my wrist pin replacement bearings are caged, not the original individual needle bearings. Do I use the thrust washers with the caged wrist pin bearings?

 

[racerone]

Do not use the caged bearings !!---Use the upgraded / improved / better individual bearings.-----Use the factory parts.

 

[Faztbullet]

Going to disagree.... I have been using the caged for years and no problems(so has Merc) and no you need not use washers. All the Hi-Po motors use em and even Wiseco supplys them. Use em and go.

 

[Terrapin]

My OEM Service Manual states, "If the upper crankcase head bearing is damaged, crankcase head and bearing assembly must be replaced". Given this guidance, I ordered a new head assembly, since I am replacing all crank bearings, but it came to me with corrosion on the bearing cage. Investigation on this site tells me I can order the bearing alone from outboardparts.com and replace the bearing in the head assembly. Is there any issue or concern with doing this given the Service Manual guidance?

 

[Faztbullet]

No......remove seal and o-ring. Place new bearing in freezer overnite. Place head on top of small coffee can. Pre-heat oven to 450° and insert. You will hear it fall out into can. Remove can and flip head over. Grab new bearing from freezer and drop in head. let cool and install new seal.