Starboard engine starts when cold, dies, won't start again

[Arkansan]

Hi guys, it's me again. It is ALWAYS something with this '98 Sportster 1800. In my last post, we were replacing the rubber boot on the PTO end of the port-side driveshaft. Thrilled to report that everything on that engine seems to be working fine, which is a darn good thing because we've had to depend on the port engine almost entirely during our last three cruises.

Here's what happens: Both engines start promptly, which makes you think all it well, but as soon as we get out of the no-wake zone and start to accelerate, the starboard engine gets to about 4,000 RMP and then dies. After that, it is almost impossible to start it again. If we do get it started, it does the same thing. My husband has messed around with the fuel/air mixture, but that doesn't seem to make any difference. He traded the sparkplugs from one engine to the other, and that made no difference at all. The battery is new. The fuel filters look fine. We tried spraying in starter fluid, but that didn't help at all. It always sounds like it's just about to start but it ... just... doesn't.

When it's cooled down, it starts again promptly. In fact, we pulled the boat out of the water about an hour and a half ago, and I just started the problematic engine in the driveway on the first try. Which is so aggravating. Put your collective brains together and tell us what we're missing. THANK YOU!!!

 

[LouDoo]

I have a hunch if you take compression readings from both engines you're gonna find the starboard engine is low. Take your compression readings remove spark plugs, ground the spark plug leads, turn of fuel, throttle open, ideally you should get 150psi.

Lou

 

[Coastiejoe]

Sadly, I think Lou is on the right track.

We have another post where it basically shut off. Assumed it was electrical. I suggested a compression test to ensure of good base engine. His was 90 in one hole and 120 in the other...

So it is worth doing the test...

 

[Guest_User]

sounds like a fuel issue, the engine is seeing load and demand when trying to accelerate and get the boat up on plane. I agree that Low compression could be a contributing factor but I don`t think Low compression would just have the engine cut off, low compression and nothing else wrong usually won`t build power.

 

[jhjesse]

Hi guys, it's me again. It is ALWAYS something with this '98 Sportster 1800. In my last post, we were replacing the rubber boot on the PTO end of the port-side driveshaft. Thrilled to report that everything on that engine seems to be working fine, which is a darn good thing because we've had to depend on the port engine almost entirely during our last three cruises.

Here's what happens: Both engines start promptly, which makes you think all it well, but as soon as we get out of the no-wake zone and start to accelerate, the starboard engine gets to about 4,000 RMP and then dies. After that, it is almost impossible to start it again. If we do get it started, it does the same thing. My husband has messed around with the fuel/air mixture, but that doesn't seem to make any difference. He traded the sparkplugs from one engine to the other, and that made no difference at all. The battery is new. The fuel filters look fine. We tried spraying in starter fluid, but that didn't help at all. It always sounds like it's just about to start but it ... just... doesn't.

When it's cooled down, it starts again promptly. In fact, we pulled the boat out of the water about an hour and a half ago, and I just started the problematic engine in the driveway on the first try. Which is so aggravating. Put your collective brains together and tell us what we're missing. THANK YOU!!!

Didn't you guys just replace the engines recently? Might start with a compression check first.
Check the external fuel pumps.
When was the last time you replaced/cleaned the fuel filters. Make sure the "O" ring on the fuel filter is not misaligned or worn. If it doesn't seal then it will def. suck air into the system.
Have checked/replaced the pulse line going to the fuel pump.

 

[pwgsx]

Bad ignition coil?