"another" power loss

[MAC ATTACK]

Brand new here. Hate to ask another power question but here goes.

1979 85 HP Johnson V-4

Just rebuilt carbs due to no idle. Changed gas and lower unit oil. Engine runs great, no missing or drops in rpm, but it will not get high enough rpm's to plane out. It just runs along at about 2500 rpm and will do it all day. Linkage seems to be getting full throttle.

I plan on checking/changing plugs today.

When I changed the lower unit oil I installed the quicksilver "blue" lower unit oil instead of my usual wal-mart oil. It seems thicker. The bottle says not to use it on engines under 75 HP? Is that due to thickness? Could the lower unit be robbing my power?

I have read through 50 or so post on loss of power so I will check plugs for dead cylinders and check linkages again, any other obvious suggestions?

Nothing else has been loosened or worked on besides the carbs.

Glad to be a member

 

[MAC ATTACK]

Re: "another" power loss

So far I re-checked linkages, float adjustments etc.

Found that 2 of my cylinders on the same bank are not firing. switched plugs and the problem stayed with the same cylinders.

What should I try next?

 

[Daviet]

Re: "another" power loss

You could try switching ign coils and see if the problem moves with the coils.
Other wise it could be a power pack or maybe a sensor problem, requiring more indepth checking.

 

[MAC ATTACK]

Re: "another" power loss

thanks. If the problem does not move with the coils then it sounds like a bad power pack? Has anyone switched power packs to further isolate?

 

[Daviet]

Re: "another" power loss

Yes, you could swapping them also.