Question on boat motor

[STEEL WOOL]

Looking for some help with an issue with my 140 Suzuki 4 Stroke. A couple years ago I took my boat in to be serviced...new plugs, oil change. The first time out after the motor had a vibration, but once at higher rpm's it seemed to go away. Motor ran fine and didn't miss at all. I returned to the shop that did the work and let them know of the issue. They tested it and said they couldn't find anything wrong. I took the boat home and ran it using the muffs. Motor ran perfect without a vibration. Took the boat out on the water again and same vibration as before. Not sure if anyone here has any ideas or what to check. I appreciate the help.

 

[eliminator]

Not an expert here at all but almost sounds like it could be a prop problem and not an engine problem---did you try a different prop and see if that helps.

 

[Rizzo]

^^what he said.

 

[AaronJ]

Ventilation plug on prop lost? I had the same problem on my Verado last summer. Had an odd number of ventilation plugs. Caused a slight vibration.

 

[LBrandt]

Sounds like prop to me. put in gear and watch closely.

 

[SDMF]

Vibration @ idle in neutral or vibration @ low RPM in gear? My 1st thought goes to fogging, and rough idle as a result on the 1st trip. That it returned would have me looking at the plugs.

1st thing I'd make sure all the plugs are tight. Then I'd take them out, gap them, make sure the ceramic body isn't cracked (like if they dropped one), reinstall, and make sure you get a good "snap" when you put the plug wire back on the top.

2. Make sure you're fuel filter is on the correct direction, there should be a little arrow and that arrow should be pointing towards the short run of fuel line going towards the motor. If it's pointing back towards the long line coming in from the tank, it's backwards.

3. Check the fuel line, especially around the bulb for air leaks

4. If this happens when in gear, check your prop ears, easy enough for them to ding it when moving with a fork-lift, tractor, or atv/utv and not even realize it happened.

5. Also, if this is happening in gear @ low speed, spin the prop when the boat's on the trailer and see if it's bent at all.

 

[guywhofishes]

stuff like this makes me sick until I figure it out

 

[STEEL WOOL]

Prop was in new condition when this started, but i have put a slight bend in one fin since that had no effect to vibration.

Where is the ventilation plug for the prop located. I know I'm an idiot.

The shop said they did re-check plugs, but it probably would be good to check again as well as fuel filter.

Thanks for the responses.

 

[AaronJ]

Prop was in new condition when this started, but i have put a slight bend in one fin since that had no effect to vibration.

Where is the ventilation plug for the prop located. I know I'm an idiot.

The shop said they did re-check plugs, but it probably would be good to check again as well as fuel filter.

Thanks for the responses.

Ventilation plugs are black plastic plugs around the base of (barrel end) of the prop. There are usually 4 of them perfectly spaced and slightly larger the size of a nickel. I agree completely with SDMF. Plugs and filters are cheap. I'd swap em anyway. Before finding the lost vent plug issue with my VRod I messed with all of the above. I was perplexed for a couple weeks.....

 

[SDMF]

5. Also, if this is happening in gear @ low speed, spin the prop when the boat's on the trailer and see if it's bent at all.

What I mean is watch the prop-shaft to see if it's bent. Try to look right @ the middle of the shaft while it's spinning and see if there's any wobble.

 

[Allen]

I see you said it had a vibration before being bent, but I'm guessing the bent ear on the prop is at least adding to this. The prop is no longer balanced, take it off and get it into a decent prop repair shop. Not doing so is hard on the bearings.

Why it wasn't noticeable before is a good question, but that's where I would start.

Other than that, the ventilation plugs are a good start as well since it sounds like it only vibrates when under a load.

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SS or aluminum prop?

 

[all4eyes]

Check the prop hub, sounds like a prop issue to me.