2005 250 HPDI Starting issues

[19jag99]

I've looked up and down the Yamaha forum page to look for my symptoms, with no luck.

The problem that I'm having is a hard start when loading my boat, or unloading my boat. When the exhaust port is submerged, then turning over sounds like a weak battery, trim it up and then it fires off after a few seconds then idles like crap until it catches up. I can go all day cranking until the exhaust gets submerged.

Any ideas would be helpful.

Thanks, Thomas.

[chaseerry]

I think I can relate. I have a 2009 HPDI Series2 that I have to "bump the hotfoot" when starting with the motor trimmed down and exhaust port in the water. I've been told by many that it's a known backpressure issue. The motor will always start with it trimmed up quite a bit.

And yes, if started with the motor down and you aren't giving it some throttle (just enough to fast idle) then it will gurgle, shake and just about die. Sometimes it will in choppy water. I think again it has something to do with backpressure and water getting in the exhaust port.

[19jag99]

I don't know if I've found part of the problem but, there is a exhaust boot under the cowl that was not sealed good. It appeared to be collapsed on the top and the bottom. Not sure what caused that but it didn't look right. Going to replace it and see if that helps.

[jackdz1]

Did the exhaust boot fix this?