1977 140hp Johnson bubble back

[micknjo]

Can anyone tell me what the Rev limiter is on a 140 bubble back. Think I'm being wound up. Was told it was only 5000 rpm.

 

[emdsapmgr]

Re: 1977 140hp Johnson bubble back

The original factory power packs for this engine were unlimited. Those have been discontinued years ago. Unlikely you still have two original factory packs. If you purchase a replacement from Bombardier today, it will have a 5800 rev limit. Just one new pack at 5800 will limit the engine to that rpms. That engine could still make strong hp over 5800. The 5800 is not a bad rpm for that engine, it makes strong torque at that point and should perform well for you throughout your ownership, if propped to run WOT at 5800. Anything less than that, (like 5200 or 5300) and you will give up hp/performance. So prop it to turn 5800 with yourself in the boat and a light load of fuel, at full trim (out.)

 

[phillnjack2]

Re: 1977 140hp Johnson bubble back

Well some thing is a bit wrong with the above statement. maybe thinking of the later engines with 2 power packs !!!.
the 1977 Johnson 140hp crossflow with the bubbleback exhaust did not have 2 separate powerpacks,
it has just the single one on the back between the top of the heads above the bubble back exhaust.

I think the question should really be is what was listed maximum rev range for this engine when new.

sorry to contradict you emdsapmgr ..



phill

 

[emdsapmgr]

Re: 1977 140hp Johnson bubble back

Sorry, you are correct, it has but one power pack.

 

[phillnjack2]

Re: 1977 140hp Johnson bubble back

and that is why it is not such a high revving engine as the later models.
I think 5500 will probably be the max revs with standard carbs and reeds and standard timing..


phill