1991 Yahama 85 HP new issue

Only had this boat for a few weeks, but it has run perfectly since I got it, absolutely no issues until last night. I was running about 40 mph when all the sudden the engine revved out and the boat stopped. I put it into neutral and quickly turned around to try and head for the ramp, I put it back into gear and it didn't really respond, I had to put it at half throttle just to do about 5-8 MPH all the way back to the ramp, if I tried to give it more gas it would kind of bog down. I checked the prop when I got back to the ramp and everything looked all right. The engine sounds like it is running great while idling and I can rev it up out of gear and it sounds great, but once I put it into gear it bogs down and takes a lot of throttle just to get it moving and it just doesn't sound right.

Any ideas?

Re: 1991 Yahama 85 HP new issue

You could check for a spun prop hub, take a look at the gear oil for filings.

Re: 1991 Yahama 85 HP new issue

bogging down will not be a prop problem, you have a fuel issue.

Water or trash in system plugging things up is my guess

Re: 1991 Yahama 85 HP new issue

I think I figured it out, haven't fixed it yet, but I think I know what it is.

I just started it up on the muffs with the cowling off, it was idling very high which it has never done before. I revved it up twice, and on the second time I could see the control arm on the block totally come off where it was bolted on, the bolt must have been very loose and while running the other night it slipped causing it to come out of gear it rev out.

Sounds like an easy fix but I cant seem to figure out how it goes back on correctly even after looking at the schematics for it.

Re: 1991 Yahama 85 HP new issue

Alright, I got the throttle put back together, and also found a hose that was leaking from the second carb.

Thinking that I've got everything fixed perfectly I just dropped the boat in the water, and it starts right up and idles nicely, backed it off the trailer, tried to give it some gas and it bogs down again. I can go idle speed perfectly and the engine sounds good, but I give it any gas and it bogs down and sounds like its going to cut out.

I am running out of ideas. The carbs were rebuilt by a mechanic about 2 months ago, the previous owner gave me the receipt so I wouldn't think it would be anything to do with them. The gas is all brand new, with new fuel filters as well.

Re: 1991 Yahama 85 HP new issue

even cleaning carbs yesterday much less 2 months ago does not mean there is not a problem in them.

Make sure your timing is still good as I think there is linkage telling that where the throttle is.

Not sure what you meant about motor revved out and boat stopped, but if timing is good then you are having fuel problems still in my opinion

Re: 1991 Yahama 85 HP new issue

99yam40 said:

Not sure what you meant about motor revved out and boat stopped, but if timing is good then you are having fuel problems still in my opinion

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I was doing about 40 mph and the motor came out of gear and the engine revved real high because it wasn't in gear anymore causing the boat to come to a stop. I pulled it back to neutral and then put it back in gear but could only go idle speed.

Re: 1991 Yahama 85 HP new issue

I put the old prop back on the boat, changed lower unit oil, re-checked throttle connected, and dropped the boat in the water. Starts right up, idles nicely, I back it off the trailer and put it in gear. It picks up a little better than before, but it still sounds like it is kind of bogging down and won't really get up and go like it did before.

Re: 1991 Yahama 85 HP new issue

So it ran a decent amount better then a few days ago and all I did was change the prop and the lower unit oil. So I am not really sure what it could be, I called a couple different places and told them what happened and none of them think its a fuel issue judging on the fact that it started with the throttle arm pretty much falling off. The one guy I spoke with said I probably just don't have the throttle rods connected properly so the more throttle I give it doesn't make a difference. And another mechanic said it could be the timing got screwed up somehow.