1995 Yamaha 200 suddenly shaking really bad at 3500rpms

Here is the story: 15 miles offshore and still running I see the starboard motor loose 1,000 rpms. It is not shaking or anything just will not pass 3200 rpms even wide open. We troll all day, on the way in the port motor starts acting up. I come in, change the fuel filters, replace the plugs and take it for a spin. The starboard motor seems to be running fine, but the port motor is all over the place. It won't pass 3500 rpms and was shaking all over the place. <br /><br />Any ideas? (Besides call a mechanic)

Re: 1995 Yamaha 200 suddenly shaking really bad at 3500rpms

Are you having trouble with both motors acting up. I'm new here but I've learn a lot by looking at other post . Look for post here that mention safe mode. Safe mode limits your RPM. If both motors are acting up sounds like your fuel tank may be a source if it feeds both motors. Carbs need cleaned, fuel pumps, fuel lines. Give these guys some more info what is the model number outboard, has it been sitting awhile or have you been using it every weekend.

Re: 1995 Yamaha 200 suddenly shaking really bad at 3500rpms

What did you find in the fuel filters?<br />What did each plug look like? <br />Your clue lies in those parts you replaced.<br />I agree with the bad fuel suggestion.<br />Does it have carbs or fuel injection?

Re: 1995 Yamaha 200 suddenly shaking really bad at 3500rpms

The motors are Saltwater series and have carbs. The filters were in bad shape, but they also have not been replaced in atleast two years. The plugs were all dirty except one. I suspect bad gas or atleast a build-up of bad gas. I just don't get why one engine seems fine now, and the other is doing the shaking thing at 3500 rpms.

Re: 1995 Yamaha 200 suddenly shaking really bad at 3500rpms

The motors are used atleast twice a month. I flush them after every use. This is really the first problems I have had in two years. They have been flawless.

Re: 1995 Yamaha 200 suddenly shaking really bad at 3500rpms

From your description it sounds like you passed water and or crud through filters that were past due changing. Now you probably need to rebuild the carbs on both engines. Don't keep running them like this, if they are running lean due to clogged orifices you will kill the engine. Order some carb kits and replace the filters. Water separating filters will remove most of the water but if they get loaded up they will pass water. They need to be changed at least every season and more often if you use the boat a lot or have a lot of condensation.

Re: 1995 Yamaha 200 suddenly shaking really bad at 3500rpms

I agree, go through the whole fuel system for sure! Time to pull those carbs apart soak, wash, blow & rebuild. I found NAPA carb cleaner in a gallon to work well. Get in the habit of changing all filters and strain fuel while fueling.

Re: 1995 Yamaha 200 suddenly shaking really bad at 3500rpms

Thanks...<br /><br />I am very technically inclined, but this is something that I should not consider doing myself, correct?

Re: 1995 Yamaha 200 suddenly shaking really bad at 3500rpms

I have no experience with that particular engine but if you can access the carbs to remove them they are not very complicated to clean and rebuild. Go to the bottom left of this web page and get a manual, order a rebuild kit (usually a float valve and a couple of gaskets), get a can of spray carb cleaner and locate a source of compressed air (important)to blow out the orifices and have at it. Basically you are going to remove the carbs, remove the carb bowls and float valve, unscrew the idle mixture jets and spray the carb cleaner and compressed air through them. Then reinstall the new float valve, check/set the float height, and reinstall the idle mixture screws to manual specs and reinstall with new gaskets. While the carbs are off and before you put them back on you should replace the water separating filters and then flush the hoses and fuel pumps to make sure all the crud is out of the hoses. This is probably a good time to replace or rebuild the fuel pump diaphragm because a bunch of crud is probably rumbling around the fuel pump too. Most outboard carbs are similar. A manual is essential to refer for specs and particulary for setting and synchronzing the linkages.

Re: 1995 Yamaha 200 suddenly shaking really bad at 3500rpms

jlara,<br /><br /> Try checking your ground wire to the problem engine, it might need to be replaced. I had the same problem with one of my 90's. After numerous part swaps and trouble shooting it came to be a bad ground. Try it, it might save you hours of headaches.<br /><br />Ikaika

Re: 1995 Yamaha 200 suddenly shaking really bad at 3500rpms

A second on the fuel pumps. I just bought my yamaha and have been having simular problems. I took the pumps apart and found that the screws inside were rusted up. After the fuel pumps I have no filter so that rust was going into the carb and ports. If you do rebuild the pumps you may want to get stainless steel screws for inside.

Re: 1995 Yamaha 200 suddenly shaking really bad at 3500rpms

Buy new pumps they are cheap ~$35.00 ea and have SS screws in the new ones.

Re: 1995 Yamaha 200 suddenly shaking really bad at 3500rpms

just replace the pumps. the parts to rebuild them are almost as expensive as the pump. it does sound like a fuel issue, it also sounds like its time to catch up on the maint. if you continue your maint practices you will find how expensive that motor can be. its time for the cooling system to be tuned up as well. also its time for the engine oil tank water trap to be drained and the remote oil tank filter to be changed as well a a whole list of maint to be done annually or every 100 and 200 hours. WHICHEVER comes first.