Johnson 150 Rebuild/Remanufacture Guidance

[Faztbullet]

Light oil on head bolt threads...peanut butter on bolts that torque under 180 in lbs

 

[Terrapin]

Light oil on head bolt threads...peanut butter on bolts that torque under 180 in lbs

OK, help me out, by peanut butter do you mean OMC Gasket Sealant or equivalent on bolts that torque under 180 in lbs?

 

[Faztbullet]

""OMC Gasket Sealant or equivalent on bolts that torque under 180 in lbs?""
This....

 

[James R]

I have been using OMC or Mercury equivalent Perfect seal on all bolts that do not require thread locker. It works very well. Same stuff on gaskets that require water sealing including the block to adapter gasket. and the lower edge of the cylinder head gaskets. These areas have a habit of weeping.
Oh, and when coating the bolts do the shanks as well as the threads. The sealant also acts as a thread locker and so easy to take apart down the road.

 

[Terrapin]

Crankcase Sealing: Do I use a 1/8" bead or even coat of Loctite 518 on crankcase mating flange? The OEM Service Manual states:
"Apply OMC Gel Seal II to the crankcase mating flange of the cylinder block. The application must cover the flange evenly and consistently without being excessive. The application must not come within 1/4" of crankcase seal rings or bearings."
However, I find a few posts of individuals suggesting a 1/8" bead only on this forum.
Secondly, don't you risk a loss of compression in the 1/4" area around crankcase seals and bearings? Would a very thin amount in this region be helpful, or is it more important to keep the Loctite 518 away from these areas?

 

[racerone]

You need to understand that this is a precision joint.-----It is a metal to metal joint.-----It absolutely has to go metal to metal for proper clamp up of those split main bearings !!----It is nearly impossible to lose crankcase compression in those areas near bearings and seal rings---You hope that 99% of the 1/8th bead of sealer squeezes out to get that metal to metal fit.-----I have measured the film of sealer on some " rebuilt " engines to be 0.008" thick.-----Done by a " club fisted " individual and bearings failed within hrs of start up.------Hope this helps you ?

 

[Terrapin]

You need to understand that this is a precision joint.-----It is a metal to metal joint.-----It absolutely has to go metal to metal for proper clamp up of those split main bearings !!----It is nearly impossible to lose crankcase compression in those areas near bearings and seal rings---You hope that 99% of the 1/8th bead of sealer squeezes out to get that metal to metal fit.-----I have measured the film of sealer on some " rebuilt " engines to be 0.008" thick.-----Done by a " club fisted " individual and bearings failed within hrs of start up.------Hope this helps you ?

Thanks for the quick reply. Yes, this helps in understanding the interface and purpose of the Loctite 518 to account for very minor irregularities. I just now used a 24" precision machinist straight edge on both halves. I checked along the bolt length on each piece and diagonally across corners. The block half is very flat with no ability to get a .002" piece of Starrett shim stock under the straight edge anywhere. The crankcase cover half is similar, but I can force a .004" thick piece of shim stock in one flange corner with resistance. I am thinking the bolt torque should pull that corner down.

 

[racerone]

All aluminum casting warp / distort with time and heating / cooling cycles.----That cover will flex and fit properly with the torque.

 

[Terrapin]

I have been using OMC or Mercury equivalent Perfect seal on all bolts that do not require thread locker. It works very well. Same stuff on gaskets that require water sealing including the block to adapter gasket. and the lower edge of the cylinder head gaskets. These areas have a habit of weeping.
Oh, and when coating the bolts do the shanks as well as the threads. The sealant also acts as a thread locker and so easy to take apart down the road.

In regard to the cylinder head gaskets, my service manual specifically states no sealant. By "lower edge" are suggesting gasket sealant on the outer edge of the gasket (not metal cylinder sealing ring) ? Is this an agreed upon workmanship change for these old crossflows? I'm curious . . .

 

[Faztbullet]

If you have the newer blackish/green gasket with a semi shiny surface do not sealer. The are silicon impregnated and will seal after a couple of heat cycles

 

[Terrapin]

If you have the newer blackish/green gasket with a semi shiny surface do not sealer. The are silicon impregnated and will seal after a couple of heat cycles

Alan, I bought the WSM gasket set from Jason. The cylinder head gasket has "Motor Gasket Molls" printed on it. It's definitely blackish with a smooth semi shiny surface. The surface feels a bit waxy, but I'm not seeing the green color. Do you think these are the silicon impregnated ones?

 

[Faztbullet]

Yep..

 

[Terrapin]

Carburetor Questions: Although this engine was running well even with a few scored cylinders, it has been 9 years since I rebuilt my carbs so I purchased three rebuild kits. In addition, although the original OEM reeds do not appear to be chipped, I can see light around a few of the reeds. I purchased a set of Chris Carson Sport Reeds with the goal of improving my idle. I'll check the reed deck surfaces for flatness and re-surface with 320 grit silicon carbide if necessary.
1. Should any of the fuel jets or idle air bleed orifice sizes be changed given current day fuels, the use of the Chris Carson reeds, or other ?
2. Do the orifice numbers equal the orifice diameter in thousandths of an inch? I want to gage pin them to confirm they are correct per the parts diagrams online.
2. What grade of fuel should I burn in this 1986 Johnson V6 crossflow?
3. I purchased a diaphragm kit for my VRO and plan to rebuild it.
Proper guidance regarding my carburetors is greatly appreciated. Thanks!

 

[Faztbullet]

1) I myself would bump em up a tad richer with new reeds & boring
2) Yes
3) Depends on which heads ya got..if stock 87 will be fine
4) Diaphragm is for fuel side , make sure you run 50:1 and monitor oil tank for oil usage
5) Use the OEM/BRP/EMP/WSM kits only.. they have the larger inlet orifice

 

[Terrapin]

Just to clarify, my engine is stock (except for the .020" oversize bores) and I just purchased the Chris Carson Sport Reeds, no "stuffer" gaskets. Per the parts break down, I should have:

• High Speed Orifice No. 56C
• Orifice No. 29
• Orifice Idle Air Bleed No. 33

Which ones do you recommend I change and by how many thousandths or to what numbers?

 

[Faztbullet]

Idle one

 

[Terrapin]

Idle one

The No. 33 Orifice Idle Air Bleed? Smaller or larger? No. 32 or 34 ?

 

[Faztbullet]

Smaller

 

[Terrapin]

Timer Base: I am reinstalling the timer base and my service manual tells me to:
"Apply a light coating of OMC Moly Lube to the crankcase head bearing surface and the timer base bushing."
Is the crankcase head bearing surface the machined outside diameter of the crankcase head that the timer base goes over?
Where is the "timer base bushing"?
If I understand correctly, the linkage to the throttle arm positions the timer base correctly and the retaining ring holds it in place, but allows the timer base to rotate?
Is there any other alignment required?

 

[Faztbullet]

The head is the recessed lip in block and the bushing is the split plastic ring on bottom of timer base.. you had it figured out