Early 80's Evinrude 35hp: power issues.

[lindeman]

I have an early 80's Evinrude 35 horse. It starts and runs fine, but I have two problems:

1. The engine loses power when the boat hits any kind of wave. Comes right back, but whenever the boat hits a wave, it loses rpms for a split second.

2. I'm not getting full power out of the engine. Under the hood, there is a rod with a a set screw part that controls how the throttle pushes the rod (port side of engine). Sorry I don't know enough to id it by name. But adjusting the set screw part as far aft as possible, I've been able to get more power out of the engine. But I don't know enough about outboards to know what I've accomplished here. I just have the sense that I'm not fully increasing the throttle.

Any help is greatly appreciated.

Lindeman

 

[lindeman]

Re: Early 80's Evinrude 35hp: power issues.

I meant to mention that a couple of times, when starting cold, the engine would run at about half power, and all at once, full power would kick in.

Lindeman

 

[Joe Reeves]

Re: Early 80's Evinrude 35hp: power issues.

DO NOT have engine running!

Spin prop so that you can put the engine into forward gear properly.

Loosen the set screw so that it can slide on the throttle rod.

Advance the throttle control to the full throttle position.... and MAKE SURE that the vertical throttle lever is hitting the stop on the cylinder block.

Push the rod to the full throttle position (check the throttle butterfly) and slide the set screw/barrel assembly up against the nylon block and tighten the set screw. (That's it)

Looses power and comes right back when you hit a wave? Sounds like a loose ground or some other loose wire somewhere. Try moving wires around when engine is at a slightly fast idle.

 

[lindeman]

Re: Early 80's Evinrude 35hp: power issues.

Thanks for your help. How do I id the vertical throttle lever, stop on the engine block and throttle butterfly (I already know the throttle rod and set screw)? Thanks for your patience with a guy who is accustomed to inboard diesels.

Lindeman

 

[Joe Reeves]

Re: Early 80's Evinrude 35hp: power issues.

With the engine in gear and not running, advance the throttle to the full throttle position. It is at this point that the vertical throttle lever (the lever the rod is attached to) should have rotated and be resting against the block.

 

[lindeman]

Re: Early 80's Evinrude 35hp: power issues.

Went to the boat yesterday. I think I'm getting full power. It just pushes my 14 foot boat 2 knots slower than my Mariner 28 horse. At wot, what I think is the vertical throttle rod is as far down as it can to. I don't understand "rotated and resting against the block."

I removed the black, plastic piece from in front of the carb (what purpose does the black piece serve?), and noticed that the flat metal covering (is this the butterfly?) always remains in the horizontal position, full open. Whether the engine is in gear, wot or idle. I'm thinking that's not right.

Can't figure why the engine is losing power momentarily. It's not a wiring issue. I tried your suggestion of wiggling wires with no result. It also loses power in a turn.

Thanks for any suggestions.

Lindeman

 

[Joe Reeves]

Re: Early 80's Evinrude 35hp: power issues.

NOTE: Do Not send me private messages when you're also posting messages on the board as that has a tendency to have me answer your questions twice. Posting on this board is best where other members can join in.

Originally Posted by lindeman.It's a '78. What I think is the vertical throttle rod is as far down as it can to. I don't understand "rotated and resting against the block." The black plastic piece from in front of the carb, what purpose does it serve? The flat metal covering (butterfly?) remains in the horizontal position, whether the engine is in gear, wot or idle. Can't figure why the engine is losing power momentarily. It's not a wiring issue. I tried your suggestion of wiggling wires with no result. It also loses power in a turn.Lindeman

With the engine in gear, observe the engine's port side. There is a vertical throttle rod running up the side of the powerhead from the bottom throttle gear to the armature plate under the flywheel. At the top portion of that rod, it changes to a horizontal extension of the rod. This horizontal portion is the part that must be up against the block (full spark advance) when the throttle is set to full throttle.

The black plastic piece keeps debris from getting sucked into the carburetor throat.

The butterfly at the front of the carburetor is the "choke" butterfly. The "throttle" butterfly is at the other end of the carburetor.

Perhaps you're having a problem explaining the problem? Does the engine race up and the boat slows down when in a turn or jumping a wake etc? If so, that's not a power loss.... that's usually called "cavitation", a condition whereas the propeller comes too close to the surface of the water and has a air pocket drawn into it.

Without actually being there, I can't think of any other condition that would cause a power loss in a turn.

 

[lindeman]

Re: Early 80's Evinrude 35hp: power issues.

I now fully understand, and have accomplished, the throttle setup. So the engine gets the boat up on plane with good power, and after about 15 to 30 seconds, begins to lose, and quickly regain, power. It sounds like the choke is being pulled and immediately repushed over and over again. Waves and turns make the problem worse. Only happens at WOT. Is this a carb issue?

Thanks,
Lindeman