Some help and advice requested

[Thumper68]

Hi,
This is my first post, but I am going to ask for help anyway. I bought a 1978 17 ft VIP fish and ski boat from a close friend of the family that need some quick cash. I paid $2900 for it and got it out on the water today. I realize that this is not the preferred way to purchase a boat, but it was better than giving him a loan or letting him get in serious trouble. Anyway it has a 1992 90 hp Johnson V4 outboard on it. Listed below are some of the issues that I noted.

Disclaimer: I did order the OMC manual for this engine before I posted here. I know it is necessary to repair and perform preventative maintenance.

1. Tilt it intermittent going down. This occurs with either the button on the side of the engine or on the throttle. I suspect loose or shorted wiring.

2. Throttle is very stiff going forward and is difficult to control engine RPM with it. Can this be cleaned and lubed?

3. Engine stalls when putting in gear (forward or reverse) unless you move the throttle lever quickly and then you get too much at once. Also noted when returning the fast idle lever to normal engine will stall if moved to normal too quickly from fast idle. Sometimes when moving the fast idle lever to normal, I can hear what I assume backfiring in the carb? It is almost a whoosh or coughing sound. That concerns me some. I do have 3 charged fire extinguishers aboard.

We still had a good day of fishing and being on the water, but this boat has not had a lot of TLC lately.

Thanks for looking and thanks for this outstanding forum!

Stan.

 

[F_R]

Re: Some help and advice requested

1. Can't answer from here. Check it out and see. But if it is mechanical, it could be corrosion where the tilt tube goes through.

2. Cable might be kinked. Replacement is the cure if it is.

3. Use that manual and go through the synchronization procedure to the letter. Also, it might just be idleing too slow.

 

[Joe Reeves]

Re: Some help and advice requested

1. Tilt it intermittent going down.......... If you hear a clicking within the plastic PTT (power tilt trim) box, the relays may be intermitent. However, check battery voltage and wiring as you suspect. Usually it's a bad relay...... switch the relays and if the problem is now the opposite (intermitent going up), a relay is faulty.

2. Throttle is very stiff going forward......... Disconnect the throttle cable at the engine. Move the throttle linkage where the cable was attached. If that linkage moves okay, check the throttle cable via the control box (move the throttle lever). If this is where the stiffness is, the usual cure is to replace the throttle cable.

3. Engine stalls when putting in gear....... First check the compression which should be approximately 100+ psi and even on all cylinders. Now, with the spark plugs removed, check to see if the spark will jump a 7/16" gap with a strong blue lightning like flame..... a real SNAP! (The 7/16" gap is important).

If the comprssion and spark is okay, the stalling problem would be due to fouled carburetors, in which case remove, clean, and rebuild them using complete carburetor kits. Kits available here, your dealership, NAPA, marine type stores, etc.

 

[Thumper68]

Re: Some help and advice requested

Thanks F_R and Joe. I will post back with any results that I get.

Joe,
Regarding the tilt, are the relays part of the motor or boat circuitry? I have never worked on a boat before but I do have mechanical abilities.

 

[wilde1j]

Re: Some help and advice requested

Do yourself a favor and get an OEM shop manual ... fleabay or outboardbooks.com

 

[Joe Reeves]

Re: Some help and advice requested

Trace the wiring from the electric PTT motor back to its plastic junction box assembly. The box is usually in with the powerhead (under the hood) somewhere. The relays will be within that box.

 

[Thumper68]

Re: Some help and advice requested

Trace the wiring from the electric PTT motor back to its plastic junction box assembly. The box is usually in with the powerhead (under the hood) somewhere. The relays will be within that box.

Thanks Joe,
Here is what I discovered tonight. I found the relays by tracing the wiring to the junction box as you said. Moved the motor up and down until if failed to go down. Swapped relays and it moved up and down fine. Repeated attempts resulted in a very intermittent not going up condition. It was so intermittent that I thought that just swapping side to side cleaned up the contacts, but I am usually not that lucky LOL. I will price out a relay tomorrow. I am not sure which one it the up or the down relay, but I am hoping when my shop manual arrives I will be able to pinpoint it. Depending on price I may just change them both out to be sure.

On this issue I found the following.
Engine stalls when putting in gear....... First check the compression which should be approximately 100+ psi and even on all cylinders. Now, with the spark plugs removed, check to see if the spark will jump a 7/16" gap with a strong blue lightning like flame..... a real SNAP! (The 7/16" gap is important).

The upper left hand cylinder ( sorry I don't even know the numbering system) spark plug wire was disconnected. I induced this while putting together a tool bag before going out on the water yesterday. I disconnected the spark plug wire to determine the plug socket size and obviously did not reconnect it. I believe that I will try it again, before continuing to troubleshoot further. I will take a compression check and check for spark just for peace of mind, but I am waiting to borrow a compression tester from a friend for now.

I didn't have time to look at anything else on the motor yet.

Thanks again for all of the help.
Stan

 

[Thumper68]

Re: Some help and advice requested

Today's update.
The tilt is fixed. Faulty relay as per Joe. Replaced both as they were not horribly expensive and kept the best one as a spare. Motor goes up and down every time on command.

Complied with a compression check with a cold engine. Didn't have enough daylight to rig the muffs to warm it up. Standing behind the engine the L/H upper cylinder was 105. L/H lower was 105. R/H upper was 100 (this was the one with the disconnected spark plug wire - see post above). R/H lower was 105. This would seem to be okay to me for a cold engine. Didn't get the spark gap jump check done as I lost my assistant to a sick child. I really think that the disconnected spark wire was my issue.

Disconnected the throttle cable and shift cable from the engine to check for roughness. It is in the cable. I will run it for awhile and see if it continues to bother me. I know it won't get better, but this may be a winter project.

Next item up for troubleshooting is the fuel quantity indicator. It is dead. I do have power (12.63 vdc) at the gauge, wire from sender to gauge ring good on an ohmmeter. Will start checking grounds next. As suspected the wiring is a mess of every color of wire running everywhere. Will take time to sort it all out.

Thanks for looking.

 

[Joe Reeves]

Re: Some help and advice requested

A quick test of the gauge...... simply ground out the sensor terminal of the gauge. If this pegs the gauge needle, consider the gauge to be okay.