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So I have the new carbs installed on the motor and I was trying to sync the carbs. It really is giving me problems. The gauges I have are still bouncing around a fair amount. I got the carbs synced as best as I could. My light was running out, so I might have to check on them again tomorrow.

I notice a huge difference in the way the engine sounds. Maybe I am being too picky, but I am still not quite happy with how the engine vibrates/shakes at idle. It is not a huge amount, but it is noticeable in the water in my test vessel….. aka garbage can.

Is this engine designed to run completely smooth or will it always have a little shake to it? Other thoughts?

Can you take a video of it running at idle? If it is really shaking I beginning to suspect a lower unit problem on motor mount problem or maybe it is just a perspective thing and nothing is wrong?

Should have only a slight vibration in Idle at 600- 800 rpms. Have you tested it out in open waters? If not be sure all cylinders are fireing (could be your only fireing 2 cylinders).
Ck spark plugs to see if they all are fireing. You can't sync carbs on 2 cylinders.
Are you useing a mercury tube to sync?

Dave

tompolak wrote:So I have the new carbs installed on the motor and I was trying to sync the carbs. It really is giving me problems. The gauges I have are still bouncing around a fair amount. I got the carbs synced as best as I could. My light was running out, so I might have to check on them again tomorrow.

I notice a huge difference in the way the engine sounds. Maybe I am being too picky, but I am still not quite happy with how the engine vibrates/shakes at idle. It is not a huge amount, but it is noticeable in the water in my test vessel….. aka garbage can.

Is this engine designed to run completely smooth or will it always have a little shake to it? Other thoughts?

It does sound like a lean condition somewhere. A plug check might help but problematic getting a good clue from only the idle. If you replaced the carb body you might have a leak somewhere around the intake manifold which can be found with acetyline or propane directed in this area. If the idle smooths out try reattaching with a little high temp silicone on the gaskets.
I've seen brand new carbs with blocked jets before - frustating!

I got too frustrated with the motor. I took it to the repair shop over the weekend. They are suppose to be able to look at it later this week. We will see what is wrong with it.

I keep thinking about selling the boat and getting a keel boat since I am on Lake Michigan and the Mac is a little light...... then I keep running the costs and realize why I never did it before. Just the winter storage will add at least $1,000 to the cost.

Just heard from the mechanic. You were right Crickey, it was a bad seal on the intake manifold. There was also one broken bolt (I did not do it, it was like it when I started) and I guess that did not help with the seal.

So for $311 they fixed the issue, synced the carbs and adjusted the throttle linkage to make everything run like it was suppose to. It is absolutely amazing that the smallest gap can cause such issues on these motors.

The best part, I dropped it off Saturday right before they closed, and they had it done today (Monday) at 11:00 am. For this time of the year, that is quick service.

I picked the boat up from the repair shop yesterday. They fixes the motor fine, but they damaged the trailer. At the tounge of the part that latched from the bottom to secure around the ball was badly bent up. I could not connect it to the car. I had them come out and look at it, and we got it to work for now by loosening the bolt int here so it does not fit as tight against the ball. I launched the baot and then returned the trailer to them, so they can fix it. I am not sure how they are going to fix it, but I can assure you that they will be fixing it, or I will be challenging the Credit card repair bill with the CC company.

This is why I like to do things by myself. I only have to worry about me swering this up.

Your tongue latch is "replaceable".

Bob