HELP...weird hesitation problem

[CLL2437]

I was able to get my boat in the water yesterday and everything was going great until I ran into a problem. I was running the boat off and on for about 3 hours while I was fishing. I decided to try a new spot and headed that way I way turning about 4500-4800 RPMs. I started playing with the trim to get the boat to ride a little better and the RPMs went to about 5200-5300 everything was fine for a few minutes until the motor started to bog and I lost all power. I quickly got off the throttle and slowed down. Then motor still had no power and would run real rough in any RPM. I was cruising at 2000 and it was still rough so I tried to give it a little. The motor then acted like it was going to stall. I was in the channel so I and a long way from the marina so I pulled it over and fished for about 45 minutes. I knew I needed to get back so I fired it up and headed back. I kept it at 2000-2300 and it was running just fine. I went ahead and got it up to 4500-4800 and it was still running fine. I continued to fish and cruise around for another 3 hours keeping the RPMs under 5K and never had the same problem.<br /><br />Does anyone know what could have happened? Were the RPMs too high? If it over heated would it cause this problem and was I suppose to hear a buzzer? I replaced the water pump. I checked the thermostat and found there wasn’t one in there. I also tested the buzzer and found it works as well. Any ideas? <br /><br />BTW… The motor is a 1989 Yamaha 90.<br /><br />Thanks, <br />Charles.

 

[Lasse Lehtonen]

Re: HELP...weird hesitation problem

Sounds like you losted some cylinders.I think it was an ignition problem cause it just went away as you told.If this problem strikes again check is there a spark in every plug.When you replaced the waterpump was the impeller went bad or did you replaced it just for to be sure?

 

[jim dozier]

Re: HELP...weird hesitation problem

Does the engine have a water separating filter? Has it been replaced recently? You may have passed some water through the carbs. Filters will pass water if they are full or damaged. Disconnect the fuel line and pump some fuel into a clear container and check for water.

 

[CLL2437]

Re: HELP...weird hesitation problem

Thanks for the replys. I changed the water pump just to be safe. I installed water separating filter a few hours before I took it out on the water. I asked around and some people told me to check the fuel pump. Does that sound right. Its just odd that I ran perfect after I gave it a rest.

 

[jim dozier]

Re: HELP...weird hesitation problem

Not likely to be the fuel pump if it got better later. Reasons for intermittent poor running are <br />-something amiss in the electricals such as a loose connection causing poor spark.<br />-crud in the fuel system causing problems in the mixture such as water or dirt. If they don't lodge permanently and pass on through the problem may be temporary but there is usually more where it came from.<br /><br />Perhaps when you were changing the filters some contaminants got into the fuel system downstream of the filters. Or perhaps they aren't on tight causing a temporary air leak. It is suspicious that the problem occurred on the 1st trip after you diddled with the system.