1986 Johnson 175 HP with Poor Reverse

[111torrance111]

I recently install a 1986 175 HP Johnson with 65 hours, it sat for almost 20 years. When purchased I had all 3 Carb's rebuilt/new lower end service (Oil/Impeller). Took the boat our and it runs great with the exception of reverse.

If I go very slow it dose back up, but if I try to give it some throttle it just sits there. I know reverse is limited when wen it comes to speed, but it's not the speed.

When I purchased the motor it didn't have a prop so I used the prop from my Evinrude 150 HP (1989) stainless steel, this prop worked great on the last motor as did reverse.

Forward I get 5200 RPM if needed, just very poor backing up. Not sure of the prop pitch.

Any thoughts would be appreciated.

Jerry

 

[racerone]

Perhaps shift cable needs adjusted ?-----Perhaps shift shaft was turned during service work.------Sounds like reverse is not fully engaging.----This has nothing to do with the prop that is now installed.

 

[111torrance111]

Interesting..

It didn't sound like it was slipping, but I'll give it a try and report back.

Thanks/Jerry

 

[boobie]

Do you notice any clunking ??

 

[steelespike]

If it doesn't rattle or jump in reverse it doesn't seem like an adjustment,
Some props have a diverter ring that helps keep the exhaust from fouling the prop in reverse.
Does the prop fit to the gear case properly so it contains the exhaust.
If the prop doesn't fit right the exhaust might just flow over prop even though you would think the
prop wash would push it away.
If it is a misfit the forward motion might contain the exhaust while under way.

 

[boobie]

Good point Steele.............If I was him, I'd try another prop.

 

[111torrance111]

No clunking, but had I heard clunking I would have assume the cable adjustment early on. Currently when going at idle RPM's it will go in reveres and backup, but give it any throttle the RPM's go up but the boat won't move.

I'll be at the boat tomorrow, I'll confirm the cable adjustment & also try another prop. I'll also look to see if the current prop seems to fit the gear case.

When done I'll write back.

Thanks/Jerry

 

[emdsapmgr]

As you are running it, you are overpropped at 5200 running @ WOT. That's a high port, big bore engine. You need a prop on that engine which will let it run up to 5750 rpm's. So, you are nearly two prop sizes (not pitches) too high. If you are running a 26, you need to be running a 22.