Help with high RPM 140 Crossflow

[jimmbo]

I am curious as to how you got the looper gearcase to fit on the Crossflow engine.

 

[Faztbullet]

I have a 1981 Johnson 140. The lower unit was full of rust and the water pump was bad, and I hadn't figured out which prop combination I need yet for the boat I put it on. So I grabbed the lower unit that was running perfectly on my 110 Evinrude (1989) @

These are the same engines just lower unit rated hp so don't expect a lot of increase...The 81 140 is a newer 110

 

[joezek]

I am curious as to how you got the looper gearcase to fit on the Crossflow engine.

The looper lower unit was a direct bolt on onto the 110. When putting onto the 140 crossflow I ended up having to modify the top of the shift rod a little bit because the forward bend on it was too early before the top. The shift rod was hitting the case, so I heated the rod with MAP gas and a little bit of reshaping with a hammer, fit perfectly. I think some years the lower unit may not bolt up because of the length of the drive shaft or number of splines. I like the Looper gearcase because it's just built more solid and worry free. With the gear ratio I ended up using a 14.25 X 17 prop. The crossflow lower unit was using a 12.75 X 19 prop.

 

[racerone]

Most looper gearcases are exactly the same as the crossflow.----Different shift rod end !-----But there are some loopers that came standard with the V-6 gearcase .--The V-6 gearcase is easily identified by the fine thread prop nut.

 

[jimmbo]

I thought the small V4 case has a 13 spline driveshaft and the big V4 loopers had a 15 spline driveshaft. Gear ratios are different between the large and small case too

 

[joezek]

Mine has the big 15 spline, different gear ratio, which needed a bigger prop. For some reason the shift rod fit perfectly in the 1989 crossflow, but had to be modified to clear the case on the 1981.

 

[jimmbo]

Most looper gearcases are exactly the same as the crossflow.----Different shift rod end !-----But there are some loopers that came standard with the V-6 gearcase .--The V-6 gearcase is easily identified by the fine thread prop nut.

When the V4 looper was introduced in 1985 it had the larger gearcase. A year or two later it was replaced by the smaller crossflow sized case. I recall it being part of a number of solutions/changes to resolve some poor performance issues. Years later, after an increase in displacement, a larger case was reinstalled.

 

[Faztbullet]

. I pulled the bubble cover to get to the thermostats. The exhaust ports and bubble had about half a pound of chunks of burnt oil and carbon.

Post some pic's as you CANNOT remove the bubble on a looper and the t-stats on on the head!!!!

 

[175se]

A 1981 140 calls for 67c jets, at wot if you push in on the primer does it pick up in rs or fall on its face? There should be maybe 2 second lag before it starts to richen, if it picks up to lean- - if it richens right away to rich. But you should look into the water issue.

 

[joezek]

A 1981 140 calls for 67c jets, at wot if you push in on the primer does it pick up in rs or fall on its face? There should be maybe 2 second lag before it starts to richen, if it picks up to lean- - if it richens right away to rich. But you should look into the water issue.

At WFOT if I hit the primer it will lose power.

 

[joezek]

I was wondering a little bit about the upper seal on the inner exhaust housing.....never knew there was one there. I replaced the lower one at the lower unit, if the top one was destroyed maybe the exhaust flow/velocity could be all screwed up.

 

[joezek]

I took the air silencer cover off, got an extra 3 mph and a little more RPM, much easier to get on plane too.

 

[joezek]

I pulled the intake today, have a set of 1977 140 carbs ready to swap in. Who knows if they'll help, but I don't like the looks of the jets in the old carbs. I can't get all the old jets out to read the numbers, and some of them look bigger than the mains in the other two. The mid jets all look the same.

I did find a crap ton of lumpy black build up behind the stuffing blocks and reeds. Also that build up was completely blocking the (4) brass jets. I have no idea what they do, I just know they were clogged, and after I cleaned them in Hopps they suddenly had screens on them that I didn't see before. They also seem to only blow one direction, and the hoses were stiff and not really sealing well. The hoses connect to the sides of the case near the bypass plates. What would be the result of those 4 hoses/adapters being blocked?

BTW, also did the intake mod since I have 2 other backups in case it doesn't work out. The intake mod I'm talking about is cutting the opening down between both carbs to open that big center area. Not really sure of the benefit, guessing more top end performance. I'll have to keep a closer eye on the jetting and plugs.

 

[175se]

Is there a maybe 2 second lag before it loses power,if so it might be overjetted, but the water is a important issue.

 

[joezek]

Is there a maybe 2 second lag before it loses power,if so it might be overjetted, but the water is a important issue.

After a complete failure with the intake mod, I put another stock intake on. I also put the carbs that were running perfect on the 110 engine, and the performance Reeds that were from the 110. As far as I know, those carbs, intake and reeds shouldn't matter even though they were on a 110 vs putting them on the 140.

Anyways, the engine has a much cleaner throttle response, but the same 4100 rpm limit. It seems to plane off pretty decent, nothing impressive though. What can I look for regarding a water restriction in the exhaust? I have noticed that the engine runs 10X stronger and smoother on the trailer than it does in the water. My jet ski was doing the same thing, and it turned out to be a failed water coupling inside the exhaust system, allowing the muffler to literally get flooded with water and choking the exhaust flow.