Yamaha F255TXRC Outboard Exhaust System Rebuild

This guide walks you through replacing the seals and gaskets within the exhaust system of a Yamaha F225 outboard, as well as rebuilding the exhaust system itself.

Watch our Yamaha F225TXRC exhaust system rebuild video above and follow the steps below to get this job done. 

Tools and Parts – Yamaha F225 Exhaust Rebuild

• Ratchet and extensions
• Socket set
• Torque wrench
• Lower unit gasket kit

Remove the Powerhead and the Lower Unit

Step 1. Remove the powerhead and lower unit from the upper casing. 

Watch the videos below if you need help removing these components or disassembling the lower unit. 

Remove the Upper Casing From the Mounting Bracket

Step 2. Disconnect the gear shift linkage and remove it.

Step 3. Remove the four bolts holding the lower cowling, followed by the cowling itself.

Step 4. Position a drain pan under the upper casing, then remove the oil drain bolt and crush washer from the right side of the upper casing. Let the oil drain out, then reinstall the bolt and washer.

Step 5. Remove the bolt holding the gear shift shaft, and lift the shaft out from the upper casing. 

Step 6. Remove the three bolts holding the upper mount cover, followed by the cover itself. Next, remove the two bolts holding each lower mount housing, followed by both housings.

Step 7. Remove the 19mm nuts from the four outboard mounting bolts, and pull the lower casing off from the outboard mounting bracket.

Watch the clip below to see the upper casing removal segment of our Yamaha F225TXRC exhaust system rebuild video.

Remove the Exhaust System and Oil Pan From the Upper Casing

Step 8. Remove the plastic hose post from the underside of the upper casing.

Step 9. Remove the bolt holding the pressure control valve bracket, followed by the bracket and the valve.

Step 10. Remove the nine bolts holding the exhaust system and oil pan to the upper casing, and lift the exhaust/oil pan assembly out from the upper casing.

Watch the clip below to see the exhaust system removal segment of our Yamaha F225TXRC exhaust system rebuild video.

Disassemble the Exhaust System

Step 11. Remove the ten bolts holding the exhaust guide to the manifold extension. Next, remove the ten bolts holding the muffler to the oil pan, and pull the muffler off from the oil pan.

Step 12. Remove the four bolts holding the exhaust manifold, and pull the manifold out from the oil pan. 

Step 13. Pry the exhaust guide off from the manifold extension, then pry the manifold extension off from the oil pan. 

Step 14. Remove the oil strainer from the manifold extension.

Watch the clip below to see the exhaust disassembly segment of our Yamaha F225TXRC exhaust system rebuild video.

Rebuild the Exhaust System

Step 15. Remove the old O-rings from the pressure control valve, then grease the new O-rings (included in the upper casing gasket kit), install them on the pressure control valve, and reinstall the valve and its bracket back into the exhaust guide.

Step 16. Remove the old seal from the oil strainer, then install the new seal (included in the upper casing gasket kit) and reinstall the oil strainer to the manifold extension. Next, reinstall the manifold extension back onto the oil pan.

Step 17. Install the new upper casing gasket (included in the upper casing gasket kit) onto the exhaust guide, then reinstall the manifold extension and oil pan onto the exhaust guide. Add a drop of red threadlocker to the ten bolts, then install them and torque them to 14 foot-pounds.

Step 18. Install the new exhaust manifold gasket (included in the upper casing gasket kit) into the oil pan, and reinstall the manifold. Add a drop of red threadlocker to the four bolts and torque them to 14 foot-pounds.

Step 19. Install the new seal (included in the upper casing gasket kit) over the exhaust manifold. Next, install the two new manifold gaskets and the plate (also included in the upper casing gasket kit) onto the oil pan, followed by the muffler. Add a drop of red threadlocker to the ten bolts and torque them to 14 foot-pounds.

Step 20. Install the new seal and gasket (both included in the upper casing gasket kit) to the muffler, and reinstall the exhaust system/oil pan assembly back into the upper casing. Next, reinstall the nine bolts holding the exhaust system and oil pan to the upper casing. Torque the seven rearward bolts to 30 foot-pounds, and the two frontward bolts to 14 foot-pounds.

Watch the clip below to see the exhaust rebuild segment of our Yamaha F225TXRC exhaust system rebuild video.

Reinstall the Upper Casing to the Mounting Bracket

Step 21. Reinstall the two shorter outboard mounting bolts into the upper mounting dampers, followed by the dampers into the upper casing and the upper mount cover. Apply red threadlocker to the three upper mount cover bolts, then install and torque them to 39 foot-pounds.

Step 22. Reinstall the two longer outboard mounting bolts into the lower mounting dampers, followed by the dampers into the upper casing and the two lower mount housings. Apply red threadlocker to the lower mount housing bolts, and torque them to 39 foot-pounds.

Step 23. Reinstall the lower casing onto the outboard mounting bracket, and torque the four 19mm mounting bolt nuts to 52 foot-pounds. 

Step 24. Next, reinstall the lower cowling onto the upper casing and tighten the four bolts.

Step 25. Lightly grease the gear shift shaft, then slide it back down into the upper casing and reinstall the bolt that holds it in place. Next, reinstall the gear shift linkage.

Watch the clip below to see the upper casing reinstallation segment of our Yamaha F225TXRC exhaust system rebuild video.

Lastly, you'll have to reinstall the lower unit and the power head to the upper casing. Watch the videos below if you need help with both.