Suzuki DT-225 Fuel issue

[gbirth8]

After many years of owning this DT225 - 2003 (EFI) I have never had an issue with it until this past weekend.

Motor always starts right up with no issues what so ever, cold or warmed up. I normally dont even pump the primer bulb on the cold start. This past weekend the first and second runs were fine, the third time after finishing at the fishing spot we had a few hundred yards of no wake zone to go through, about halfway through the engine began to spit and sputter and eventually cut out. I thought hm weird never had this issue before. Pumped the bulb back up firm, started right up and finished our idle over.

After that we fished that area for about 45 minutes, went to go get on pad to leave to the next spot and it did the same thing just this time under load. It spit and sputter but did not quit. Hit the primer bulb (probably 10 times to get it back firm and reprime the system) boat was fine on pad no hiccups. It did this a few more times throughout the day where it would idle fine but trying to get on plane it wouldnt. After repriming as long as the motor stayed on it seemed to be fine the problem only presented itself after motor not running for a period of time.

My initial thought is primer bulb, I do not know how old it is and it is laying flat (just learned that it should be mounted vertical) although i haven't had an issue until now.

My second thought was low pressure fuel pumps (2 of them) not delivering enough fuel to the VST for the electric HP pump to then take over from there, but then i second guess myself due to the fact that once i re-prime the system with the bulb it is all good for as long as I was running the motor which was not super long but long enough it should have starved of fuel again.

This brings me back to just a bad primer bulb, or possibly a partially clogged filter. Air in the fuel system somewhere between LP pumps and tank? which i think would present itself while i was running WOT.

Last bit of info is after i got home i pumped the primer bulb for shits and gigs just until it was firm, it held its firmness for a decent bit. Can a primer bulb issue not present itself until the motor is started and that vacuum then causes one of the valves to malfunction?

It was exceptionally hot for around here the day on the water, vapor lock issue? would explain how it idles fine but when accelerating the fuel pumps cant beat the vapor lock causing it to bog back down, after repriming with bulb and vapor is gone the engine performs flawless??

I am semi-mechanically inclined but i do have a shelf

Thank you in advance for anyone reading this

[Moonlighter]

My first thought would be a partially blocked fuel filter.

Had a very similar thing a few years ago with my DF115 4 stroke. Almost exactly as you described. I managed to get home by gently pushing it onto the plane and keeping it at a slow planing speed.

Obviously I had picked up a load of dirty fuel and it had almost blocked the Racor water separating fuel filter element. On inspection at home, I could actually see particles of debris in the clear bowl under the filter element.

I simply replaced the filter element, and then replaced it again after another 20 hours engine time - working on the assumption that the contamination is typically going to be at the bottom of the tank and by replacing the element twice, it should get most if not all of the contamination out of the tank.

Worked as expected.

I dont think its the primer bulb for reasons you explained, it pumps up firm and stays that way. My money is on the fuel filter between tank and engine.

[gbirth8]

I haven’t ruled that out and am probably going to replace it anyways for good measure as it hasn’t been swapped since I acquired the engine a few years ago now.

The only thing shying me away from it being the main culprit is the fact that after I reprice the system then the motor runs top notch. I don’t have to feather it or anything I can hop on plane and run WOT without any hiccups. If the filter was partially clogged I would think I’d have felt some sort of hiccup at some point after the reprime.