Idle and Fuel Issue

[gvilleBAMA]

Hey everyone!

1. I just want to thank everyone for all of your insightful help. I just replaced the water pump in my motor, and with the help of the info on this forum (and my shop manual) it now pumps amazingly.

2. Now my current issue. I have a 1989, 40hp Evinrude (Tracker Addition)...Before i replaced the water pump it would start and idle fine, under full power it would plane off quickly and top out around 30 (according to the speedo), and turned around 5200 RPMs. Today I took it out after the water pump replacement and it had a terrible idle and would only turn about 3,000 RPMs at full throttle (wouldn't quite plane). Right now I'm think some sort of fuel problem (starvation). Any ideas or help would be great.

Thanks in Advance,

Nathan Z.

 

[Barnacle_Bill]

Re: Idle and Fuel Issue

A start would be to check all your fuel line connections and the line. Especially the primer bulb. As they get old they get hard and can develop cracks causing air to be sucked in in line.

 

[iwombat]

Re: Idle and Fuel Issue

Dropping the LU should have nothing to do with affecting performance in that way. Is there some other operation that was performed on this motor or boat? Think hard.

 

[gvilleBAMA]

Re: Idle and Fuel Issue

No other operations....Took it out about 2 weeks ago and it overheated (slow kicked in). Used the trolling motor to get back to the slip (we were close). It sat for 2 weeks waiting for the OMC water pump kit to arrive. The only other thing that was done was I checked the compression in both cylinders (120lbs in both....they were cold).

 

[iwombat]

Re: Idle and Fuel Issue

Well, the history helps tons. Have you checked compression since the overheat? It wouldn't be uncommon to warp a head or blow a head gasket.

Edit: You just said you did - D'oh! I should read more carefully next time. Might want to re-torque the head bolts in any case.

 

[gvilleBAMA]

Re: Idle and Fuel Issue

I'll do that....and the overheat def. was my reason for checking the compression.

I took the hood off while we were on the river today....when looking that the fuel filter...should it totally fill with gas? Only about the bottom 1/4 had fuel in it. I'm wondering if i may have an air leak in the system. I don't have a u-joint for my sockets so i removed the lower cowling to get to the bolt that held the shift rod in so i could replace the water pump. I wonder if I messed a hose up in the process.

 

[Silvertip]

Re: Idle and Fuel Issue

Since you had to disconnect the shift rod which just happens to be located directly beneath the bottom carb, there is a very fair chance you disturbed something on the throttle linkage. Better check things in that area carefully. My bet is the carb throttle plates are not opening fully. They should be perfectly horizontal in the carb bores whent he throttle lever is full open (PLEASE make that check with the engine off).

 

[gvilleBAMA]

Re: Idle and Fuel Issue

Ok...I've checked the following:

Checked the Spark.....strong on both plugs
Checked Compression......120 in both cylinders

This afternoon i'm going to pull the lower cowlings back off and see if maybe we pinched a line, of if I bumped something out of place when we put the shift linkage back together.

 

[gvilleBAMA]

Re: Idle and Fuel Issue

ok...today i removed the bottom cowling again. When I put the bolt back in the shift linkage the other day i broke the clamp for the hose that attaches from the VRO pump to the crank case. I replaced this clamp but i still have the same problem.

A couple of questions:

1. Since this clamp was loose do i have to reprime the VRO pump?

2. When the motor is running should I be able to see a flow of fuel through the fuel filter? I can see any sign of gas in the filter while the engine is trying to idle.

Also:

Once warm it runs really smooth at idle for a second or two....then it is rough and will finally quit.

I checked the compression today after the engine was warm. about 118 in both cylinders.

Thanks to everyone for the help...and HELP!

 

[gvilleBAMA]

Re: Idle and Fuel Issue

bump

 

[gvilleBAMA]

Re: Idle and Fuel Issue

OK...found my problem

The previous owner put autolight plugs in the motor. The tip for the plug wires screw in the end of those plugs....yep...they were both loose. They have both been replace with .30 gapped champions.

She idled the second time i turned the key!

Silvertip: I do believe it needs a link-in-sync...it is seems to be idleing a little high (1,800 rpms - in a barrel). I read my shop manual tonight to be sure. I'm going to take it out in the morning so i should know a little more then....again...Thanks to ya'll that helped me. I hope to give back myself. When I do the link-n-sync I plan on video taping it!

Thanks,

Nathan Z.