2000 Islandia High RMP/Low Speed and Voltage Regulaor Rectifier melting

[Optimus]

Hi all,

I purchased my first boat a “2000 Islandia” with a 240hp Mercury EFI Jet Engine, back in November 2021. Now that the boating season has started and I am all excited to get on the water, it seems that I am running into few issues.

The first one is speed. While the RPM can reach 7000 on almost full throttle, my speed does not go over 15MPH/30kmh. On my test drive, the boat could reach 60kmh. What could possibly be the issue?
Also, what kind of speed should I be expecting out of this boat?

The second issue I have is the “Voltage Regulator Rectifier”. Yesterday while taking the family out for a cruse, I started smelling what it seemed to be wires burning. I immediately stopped the boat and opened the engine compartment, and I saw white smoke coming out of the right side of the engine. It was the regulator and wires melting. I turned off the engine and luckily the smoke stopped. What could cause this part to melt like this?

Is it possible for the two issues to be related?

New replacement parts:
- Battery
- Spark plugs
- Fuel Filter

Any advice would be greatly appreciated

 

[ripcuda]

Low speed could be a worn jet pump impeller and/or wear ring. Or some debris stuck in your jet pump.

I had a bad voltage reg on my 240... it would blow the fuse repeatedly. Check your fuses, ensure you have the correct fuse (if too large a fuse, could allow it to get extra hot and smoke). You will need to replace the voltage reg... but also ensure you remove and clean all your ground cables/connection points... and your positive cable too while at it. Bad grounds can add a lot of resistance. Also ensure your battery is healthy and charged. A bad battery can cause voltage reg issues.

 

[Tim75]

Low speed could be a worn jet pump impeller and/or wear ring. Or some debris stuck in your jet pump.

I had a bad voltage reg on my 240... it would blow the fuse repeatedly. Check your fuses, ensure you have the correct fuse (if too large a fuse, could allow it to get extra hot and smoke). You will need to replace the voltage reg... but also ensure you remove and clean all your ground cables/connection points... and your positive cable too while at it. Bad grounds can add a lot of resistance. Also ensure your battery is healthy and charged. A bad battery can cause voltage reg issues.

I notice a loose bolt on your reg. The back of the regulators should be clean. The plate they mount to should be clean, too. That plate is a heat sink for the regulators. A little heat transfer compound will help. The bolts should be secure.

A bad battery will kill regs. If the battery is hard to charge, it has an internal short that can be bad for the regs.

7000rpm is definitly over-revving. Simple check with a flashlight: Look up int the jet tunnel. It does not take a large piece of junk to cause your issue. While you are there- what is the condition of the leading edges of the blades?

 

[Optimus]

Thank you gentlemen for your feedback
I checked the jet tunnel and didn't really find anything in there. I have uploaded some pictures.
However, above the jet pump housing, I found this grey tube which can disconnect very easily by hand. Is that something normal? Any idea what else can possible cause the low speed?

As for the voltage regulator, I loosened the bolt up when I was looking at it. I just finished installing the new one and I notice there is a second one below it. Either way, I cleaned all the wires and connection points on both. The difference between the two is that the lower one had the grey wire connected to something. However, the one I replaced, the grey wire does not connected to anything.

 

[ripcuda]

While visually confirming no junk stuck in the jetpump or wrapped around the driveshaft is good... it's hard to gauge how worn-out the wear-ring/impeller without pulling the jetpump apart and more closely inspecting.

The grey hose is the bilge siphon hose, when the jetpump is spinning (when engine is running), it creates a suction on the hose to help suck out water of the bilge around the base of the engine. Push hose back on and put a zip-tie on it for good measure.

There are dual voltage regs on these engines. And yes, the grey wire (for tach rpm signal) only connects to one of the volt regs... this is normal.

With new voltage reg... are you getting proper charging voltage at the battery while running now?

 

[Tim75]

Thank you gentlemen for your feedback
I checked the jet tunnel and didn't really find anything in there. I have uploaded some pictures.
However, above the jet pump housing, I found this grey tube which can disconnect very easily by hand. Is that something normal? Any idea what else can possible cause the low speed?

As for the voltage regulator, I loosened the bolt up when I was looking at it. I just finished installing the new one and I notice there is a second one below it. Either way, I cleaned all the wires and connection points on both. The difference between the two is that the lower one had the grey wire connected to something. However, the one I replaced, the grey wire does not connected to anything.

About that gray hose- It does exactly what was said. But-- there were issues with the hose itself. It can delaminate inside, with no visible damage. Flow can be completely blocked. Check your hose for flow, just to be sure.

Your stator is showing substantial damage to the vanes. I believe this is some of the damage that Impros can repair. If you need wear ring repair, they put a stainless steel sleeve in it and match the impeller to it. Bulletproof, unless you suck up rocks. What we can see in your pic looking up in the tunnel, looks like the leading edges of impeller blades are OK.

I also noticed that your control cable is missing its rubber bellows. That cable may be junk because of water intrusion and rusting. Those rubber bellows is all that keeps water out of the cable. Mercury lists them as yearly maintenance items.

 

[Optimus]

I tried to pull out the jet pump apart, but those bolts were really stuck and I didn't wanna break them if I push any harder. I looked more closely and took few more pictures. The wear ring does not look very smooth, but I am not sure if it looks bad enough to limit the speed on the boat. I also noticed few small broken pieces off the blades on the jet drive blade.
Could the wear ring and the small broken pieces on the blades really impact the speed that much?

As for the voltage on the battery, it measures 12.36V when the engine is off. I tried to turn the boat on with the water hose, but it wouldn't start. You hear the high pitch and you hear the engine trying to kick in for a sec and then it turns off.
I had that problem few times this year. One those times was two weeks ago when I was in the water. I went back home and tried with the water hose connected and the boat turned on with no issues.

I tired to make an appointment with a mechanic, but they are all booked until the end of July.

I hope these new pictures will be more helpful than the last ones

 

[ripcuda]

Saw your post on FB. I'll repeat what I posted there. Your jet pump is in very poor condition. The stator leading edges are trashed... huge chunks missing... must of chewed on some big rocks. And your impeller to wear-ring clearances are huge. You are loosing a lot of thrust there. I would bet your speed (lack of thrust) issue and over-reving engine... are all caused by your trashed jet pump. I'd be looking for a replacement. GL.

 

[Optimus]

Saw your post on FB. I'll repeat what I posted there. Your jet pump is in very poor condition. The stator leading edges are trashed... huge chunks missing... must of chewed on some big rocks. And your impeller to wear-ring clearances are huge. You are loosing a lot of thrust there. I would bet your speed (lack of thrust) issue and over-reving engine... are all caused by your trashed jet pump. I'd be looking for a replacement. GL.

Thank you so much. What parts do I need? I am not too familiar with all the terms

 

[Tim75]

Thank you so much. What parts do I need? I am not too familiar with all the terms

Get your favorite penetrating oil and spray the bolts where they enter the casting. Those bolts are stainless steel and not as strong as good steel bolts. The bolts don't corrode, but the aluminum does. It can lock a bolt as if it were welded.

After you get it apart, send pix to Impros and they can tell you if it's junk or repairable.