Tohatsu 18 HP Pump Gaskets

As no part is eternal, manual recommends a total engine check after 300 hours. Both gaskets are bit hard and show concave/convex fabric wear, was wondering : if continue to use same, will you experiment a low gas pressure in what throttle range, at idle, medium or wot ? any ideas ?

Happy Boating

Re: Tohatsu 18 HP Pump Gaskets

Luis,

The fuel pumps on these are capable of delivering a lot more volume (2 or 3 times as much) than you would normally use. Until the diaphragms develop a hole/tear, they will keep on pumping. However, the check valves can start leaking... that, in combination with stretched-out diaphragms, could lower the low-speed volume significantly. If the pump is severely worn out, you might starve for fuel after a few minutes at WOT, but it would have to be just about worn out. In our shop, if the diaphragms look stretched-out, we replace them, because the next sign of wear will usually be a tear, rendering the pump inoperative, and the labor to inspect them is more expensive than the parts themselves.

Re: Tohatsu 18 HP Pump Gaskets

Hola Paul

Both check valves looks in order, completely plain against respective base, have replaced both gsakets, will check latter at sea if this was the cause for fuel starvation at wot and intermittent performace between idle speed and full throttle, fingers crossed.

Happy Boating

Re: Tohatsu 18 HP Pump Gaskets

You do not need to replace the fuel pump gaskets and diaphragms until they are hard...This is one of those occasions where the maintenance schedule can be ignored with safety.

Re: Tohatsu 18 HP Pump Gaskets

TOHATSU GURU said:

You do not need to replace the fuel pump gaskets and diaphragms until they are hard...This is one of those occasions where the maintenance schedule can be ignored with safety.

Click to expand...

TG, thought that both gaskets could be used a while more and ignore the factory service recommendations, will give 50% credit on this one. With gaskets changed and warmed engine, throttled to wot and bang the rib went instantly, thought had placed a new engine, now performing right at idle, medium and wot. Have added a brand new fuel hose to work evenly with new pump gaskets.

Paul was right about losing some pressure. Definitively, parts to have in mind if throttle performance is not constant at all ranges.

Happy Boating