787 Motor Firing

[Jnz]

I have been trying to get this boat running and have one motor that runs great the other sounds like its on one cylinder or something. Rechecked compression and have 150 both cylinders. Carbs have been rebuilt with Mikuni kits and new needle and seats. Pulled the plug wires and cranked and the plugs are wet so it's getting gas. Fresh plugs and snipped wire still sounds off. I tried unplugging the rectifier, still no change. Swapped coils from good running motor and no change . Took a video and have included it with spark testers to show spark and hear how it sounds.

Thanks for the help !


https://drive.google.com/file/d/0B_--Sf3HlXVEendBdGlGZ3ZnUzQ/view?usp=drivesdk

 

[Jnz]

I have narrow this down to an adjustment on the throttle cable as the sound above is the rev limiter hitting.

 

[racerxxx]

You're bouncing off the rev limiter. Was the control handle in neutral? If so you'll never get off the low RPM rev limiter of 3500ish RPM. If you're in F or R and it's doing that you're neutral start switch is bad or out of adjustment. It's a simple switch you can check continuity on.



[video=youtube;Zoxqd7HMlto]https://www.youtube.com/watch?v=Zoxqd7HMlto[/video]

 

[Jnz]

Yeah this is in neutral at idle though. I'm trying to get the cables adjusted as the idle screw does nothing I can back it out all the way and it's still hitting the limiter. I believe it's cable related as the oil cable is out of threads to adjust and it still needs a little more to be lined up. The thing is, I did both motors the same and the other is idling right at 3 out of the water. Would there be something under the shifter I need to adjust?

 

[racerxxx]

Look into the carb bodies, if the butterflies are open more than the other engine something is out of adjustment. These boats have the LSS (low speed steering) it will raise the idle when you turn full lock on the steering wheel, make sure your steering wheel is centered. It sounds like you might have the cables all messed up. With the cables off the carbs all together what does it do? If it still hits the limiter your butterflies are open. watch the clips under teh carb mounting screws, they can interefere with the linkages.



#69 are the clips I'm referencing

 

[Jnz]

I actually disconnected the low speed steering to rule that out and because I'd prefer to use the throttle on my own. I will disconnect the cables and see if it idles right. Does the cable need to be adjusted under the shifter at all?

 

[Jnz]

It's just odd because if I hold the throttle open and adjust the cable to that it should be perfect right ? For the idle screw to do nothing it has to be stuck open. That and the oil cable adjuster out of threads.

 

[snikwad003]

Get it fired up then put it in fwd and see what happens because the out of water idle is 3k so is the netural limiter

 

[Jnz]

 

[Jnz]

[MENTION=16022]Dr Honda[/MENTION] does this pic work?

 

[racerxxx]

Just disconnect everything from the carbs. Isolate the carbs, start engine, if it hits the rev limiter the carbs are your first issue. The rev limiter is 3500 rpm, idle is 3k

 

[Jnz]

 

[Jnz]

On it. I'll report back in a few

 

[Jnz]

With no cables attached I'm back down to 3 and idling nice. Any advice on how to get these cables working right ?

 

[BoLongo]

These boats have the LSS (low speed steering) it will raise the idle when you turn full lock on the steering wheel

I do not want to hijack this thread, so please finish helping Jnz. Once this issue is resolved; can you give more information about the LSS? When I turn the steering wheel to the stop the idle increases. This is very annoying I was going to try and fix it. Are you saying it is supposed to do that? What is the reason?

 

[Jnz]

That is how it is supposed to be to help with docking

 

[Jnz]

In regards to my question now that I have the idle adjusted with out the cable I loosened the cable in the front shifter to give slack in the back, but how can I make sure when I put the cables on now it doesn't pull to tight again

 

[BoLongo]

RacerXXX has way more experience than me, so I was going to let him help you

But here is my attempt at it:

Every time you remove the carbs you have to go through the synchronization procedure because the distance between the carbs has changed.

Step #1 Adjust the throttle cable; I usually push the throttle all the way open and adjust the cable, so it is just opening to full throttle.

Step #2 Back out the idle screw and sync the throttle linkage.

Step #3 Adjust the oil pump cable, so the marks align

Step #4 Start the engine and adjust the idle speed.

You have to go through this procedure in this order.

Are you sure the throttle linkage between the carburetors is set correctly? You can have the throttle cable right on the Mag carb, but if the linkage adjuster is not synced correctly, the Pto carb will be off resulting in your issue with the oil pump cable.

 

[BoLongo]

Sync adjuster

 

[racerxxx]

Halt, don't adjust the rod. Let's get cables working first. I would not have adjusted by the controls at all yet. I'll help you out but can't post much at work. Stuffing my face now. I'll post up when I get some time later on. Sorry about that.

 

[Jnz]

Sounds good. I'm at work my self now ill get a chance to get back to it in the morning. Hopefully be a man with a plan.

Thanks for the help. Also should I be adjusting the cable back to wear it was at the shifter. The cables were almost even under the shifter with equal threads, I loosed the left to give me more slack in the rear at the carb.

 

[racerxxx]

Please post a pic of the carbs on the other engine please. I think you might have given me the big puzzle piece.

 

[Jnz]

Do you need the spark arrestor off?

 

[racerxxx]

Yes if you don't mind

 

[Jnz]