Monsoon 5.7 Runs rough/over heated!

[John E.]

2004 LXi approximately 400+ hours on Monsoon 340

purchased in 2006 w/ 250+ hours

winterized and stored in NH every winter

Hi All. I haven't been on the site for a while partly because my LXi has been running really well since I got it in 2006. This year a bit of a different story. The first time I ran it this year was in early April. Summerized it and took it out for a test ride. Started right up and ran well, had it out for about 25 minutes. I let it warm up and get up to running temp (160) then brought the throttle forward and ran it at 30 mph for a few minutes at a time.

Second time out it started right up again and idled well, but when I advanced the throttle after it warmed up it ran rough and would not accelerate. I reved the engine w/out putting it in gear and then tried it again. It reved fine so I tried it in gear, ran fine too for the rest of the outing including two skiers.

Yesterday (3rd time out) started and idled fine again but ran rough when I advanced the throttle (after it warmed up) so I reved the engine again, this time it the engine temp rose to 220+ and some oily smoke (not a lot but noticeable) out of the exhaust. I idled it back to the dock while watching the temp - no hotter no cooler - stayed about 220. So I shut it down and called it a day.

Living up here in the north the boat is stored from mid October until April. When I put it away last winter it had about a third of a tank of gas. I added the appropriate amount of stabil (maybe a touch more because the fuel quantity gauge isn't the most accurate. When I summerized it I filled up the tank with premium to dilute the stabil and the old fuel. I has worked every year before so I wouldn't really suspect the fuel.

My initial thought was that the impeller failed, but when I took the cover off it appeared fine. I turned over the engine and it spit out some water. Maybe the water pump has failed.

I don't know, I'm at a loss for ideas and I hope I've given enough information for some insightful feedback. I can take it in for service if it's over my head, but if it's a realatively easy fix and there are some things I can check before I go that route I would rather do that. thanks in advance for your help.

John

[dlb]

The impeller may look fine but......

I had the same issue, replaced the impeller and gasket and everything reverted to normal.

The impeller may be tested at idle, it can draw 5 gallons out of a bucket in about 15 seconds. Do not test it with a fake a lake or flush pro as they have water under pressure.

It is not uncommon for the rubber on an impeller to glaze and no longer seal or for the gasket to fail and leak air. Either will cause over heating.

[areamike]

Did you leave the impeller in the housing the whole time it was winterized? When was the last time you replaced it? I'm sure many others will chime in, but start simple at first.

[John E.]

Hey Guys,

Just wanted to give you an update.

To answer your question, I DID NOT pull my impeller last fall, it stayed in the boat all winter. I usually DO pull it so as soon as you mentioned it I ordered a new one. Long story short, I installed it today, took the boat for a test drive and it ran like a champ. Many thanks for helping me get the boat back on the water.

When I pulled the old impeller it was clear that a winter in the boat caused it to become deformed. Tried to post the photo but unable to post the image URL on my MacBook.

Thanks again!

John

[areamike]

Hey Guys,

Just wanted to give you an update.

To answer your question, I DID NOT pull my impeller last fall, it stayed in the boat all winter. I usually DO pull it so as soon as you mentioned it I ordered a new one. Long story short, I installed it today, took the boat for a test drive and it ran like a champ. Many thanks for helping me get the boat back on the water.

When I pulled the old impeller it was clear that a winter in the boat caused it to become deformed. Tried to post the photo but unable to post the image URL on my MacBook.

Thanks again!

John

Yep. That's exactly what happens. I always take mine out. Glad you got it resolved!