Strbd Engine Comm, Port low max WOT-engine rattling

[amcorley]

Morning All,

New to the forum, new to boats, new to jet boats, marginal mechanic (I can do most anything with directions). I have a new to me 2012 242 limited S, newish batteries (couple months), recent oil change (per previous owner, couple months). I bought the boat 6 weeks ago and and have run it nearly every weekend since with no issues on the boat... tubing, fishing, relaxing. I always run the vents for a couple minutes and let it warm up a bit before going WOT.

Last outing everything went as usual, pre launch checks complete, engines started right up an got out of the no wake zone. Once we got going I saw an intermittent Engine Comm Error on my starboard tach off an on throughout the three hour trip (some slow tubing ((the tach was making me nervous)) and sitting at a beach). Shutdown the boat and killed the batteries for a reboot and the same error presented later. The engine seemed to be running fine other than the tach. While tubing I noticed the starboard engine was making it up to 7K ish (when the tach was working) but the PORT engine wasnt keeping up at high RPMs. After 4K the port engine lost ground (comparing the tach display when it worked) eventually maxing at 6K while the starboard made it up higher. Cleaning out the engines afterwards the port engine had a noticeable rattle when compared to the starboard engine. I did NOT notice any more comm errors during cleanout. I scrolled through the search for similar issues but couldnt find anything definitive.

Oil levels look good, battery terminals look good, Hull looks clean, pulled the clean out plugs and didnt see any impediments on the shaft. I know the air filters are old but I dont have new ones and am leery of pulling them out long term.

Thoughts?

v/r
another noob

 

[amcorley]

bump. Need some experienced folks thoughts.

 

[Acard7]

Have you pulled the pumps just in case there was something lodged in the impellers making it rattle? Have you started it on the hose with the engine hatch open to see if you can hear the rattle? Sounds like if the port wasn’t keeping up even at higher RPMs it seems something may have been stuck. You can always pull the pumps and run the engine to rule out the impellers making the noise too.

 

[Acard7]

[USERGROUP=9]@HELP[/USERGROUP] might as well tag the help hotline

 

[amcorley]

Have you pulled the pumps just in case there was something lodged in the impellers making it rattle? Have you started it on the hose with the engine hatch open to see if you can hear the rattle? Sounds like if the port wasn’t keeping up even at higher RPMs it seems something may have been stuck. You can always pull the pumps and run the engine to rule out the impellers making the noise too.

Started it on the hose with the hatch open yes. That's how I heard the rattling comparing it to the other engine.

Don't know how to pull the pumps. I'll google it and do it tomorrow and get back to you.

 

[Bruce]

Spark plugs are a common solution when one engine loses RPMs.

The comms issue could be a connector issue or a tachometer issue. I would disconnect the cable connectors, look for issues and reconnect.

 

[Acard7]

Started it on the hose with the hatch open yes. That's how I heard the rattling comparing it to the other engine.

Don't know how to pull the pumps. I'll google it and do it tomorrow and get back to you.

look it up how to do it on here or YouTube, plenty of pump pull threads and videos! Look up the FAQ section in the drop down menu on the top left of the webpage!

Here’s one:

https://jetboaters.net/threads/yamaha-jet-pump-disassembly-from-grant-browne-youtube.446/

 

[amcorley]

Spark plugs are a common solution when one engine loses RPMs.

The comms issue could be a connector issue or a tachometer issue. I would disconnect the cable connectors, look for issues and reconnect.

Thanks Bruce. Those seem like an easy fix. I'll swap then out and see.

 

[amcorley]

look it up how to do it on here or YouTube, plenty of pump pull threads and videos! Look up the FAQ section in the drop down menu on the top left of the webpage!

Here’s one:

https://jetboaters.net/threads/yamaha-jet-pump-disassembly-from-grant-browne-youtube.446/

Appreciate the link. I'll give it a watch and give it a go tomorrow.

 

[Bruce]

No harm in pulling the pump to take a look but it is common for Yamaha boats to sound like a rock tumbler outside of the water.

When I changed the rear pump bearings on mine that sound went away for a few months.

I doubt that the low rpm and comms issues are related to anything in the pump.

 

[4x15mph]

2012, could have swollen pump housing assembly. The part that surrounds the impeller and this is very common with age. I would just check that you don't have any bad wear spots or even holes on the impeller housing. There is a specified clearance in the service manuals but I don't know that number. If you can run fishing line around the impeller and between the housing you have enough clearance.....

I would double check that you are not overheating. First thing to check is thatt you have good flow of water out the side cooling outlet holes. You have 2 on yours so check that you have good flow out of both and you will need to do this on the water. Running on hose does very little for diagnosing RPM type problems since you are not under load.

I don't have any experience with Comm errors specifically. You should be able to search on this since it is a 2012 and this problem has been solved before.

 

[amcorley]

2012, could have swollen pump housing assembly. The part that surrounds the impeller and this is very common with age. I would just check that you don't have any bad wear spots or even holes on the impeller housing. There is a specified clearance in the service manuals but I don't know that number. If you can run fishing line around the impeller and between the housing you have enough clearance.....

I would double check that you are not overheating. First thing to check is thatt you have good flow of water out the side cooling outlet holes. You have 2 on yours so check that you have good flow out of both and you will need to do this on the water. Running on hose does very little for diagnosing RPM type problems since you are not under load.

I don't have any experience with Comm errors specifically. You should be able to search on this since it is a 2012 and this problem has been solved before.

Thanks 4x15. I pulled the impeller and housing yesterday. Teeth on the impeller shaft and blades look clean. Didn't run fishing line to check clearance. I'll do that. I'll also inspect the housing. I didn't give it a good look when I pulled it but I dont recall any holes or excessive wear.

Water flow is good for both engines