A few issues from over the weekend

[dsw222]

Well this was the first full weekend that I was able to spend on my 97 Challenger 1800 and it was a great time! The boat hit 62mph with only my girlfriend and i riding it (speedo, not gps) so these issues shouldn't be affecting performance, but I'd like to get it running as good as possible

I just noticed a few things, and wanted to see if you guys think I have the right idea of how to fix them...

Problems:

#1 - The starboard engine tachs out at 7200 as i believe it should, but the port engine only reads 7000 (See attached pic). Maybe the tach is just off? Or it could be related to the next issue...

#2 - The port engine's throttle cable sticks at 5000 RPM sometimes. I will throttle both engines together until the levers are completely maxed out, but the left tach will only be reading 5000 RPM. But if I move the left lever back and forth a few times, the engine will reach 7000 RPM. Both levers are a bit "sticky", as in they aren't as responsive as I thought they would be.

#3 - The levers are not synced together. If i move both of the levers together, one engine will tach about 1000 RPM higher than the other. For example, in order for the engines to both be tached at 5000 RPM, the left lever needs to be about 2-3 inches in front of the right lever.

#4 - When I throttle the engines, the port side engine tends to stall out. It will get to around 3000-4000 RPM where it beings to sputter a bit, and when i give it more throttle at this point it will stall out. This seems to ONLY be an issue when the boat is not warmed up. I noticed it when i first put the boat in the water and also after we pulled up anchor after swimming for an hour. After the boat has been running a while, the engines throttle up fine.

Possible Solutions:

#1 - Adjust throttle cables to make sure the throttle is opening all the way before the lever hits the top of its range of motion.

#2 - Lube throttle cables

#3 - Sync throttle cables by setting one engine to 3500 RPM and adjusting the other, as outlined in the shop manual

#4 - I have no idea what could be causing this. Maybe my carbs need cleaned?

I'd appreciate any help or guidance you guys can provide! Thanks

 

[Dr Honda]

I wouldn't keep running it until you rebuild the carbs on the port engine. What you describing is a plugged up carb. If you keep pushing it... you are probably going to burn up th engine from running it lean.

Now... with the 800 engine... you could just have sticky RAVE valves... But they don't make the engine stall.

Don't worry about syncing the engines until you do a rebuild.

 

[dsw222]

I wouldn't keep running it until you rebuild the carbs on the port engine. What you describing is a plugged up carb. If you keep pushing it... you are probably going to burn up th engine from running it lean.

Now... with the 800 engine... you could just have sticky RAVE valves... But they don't make the engine stall.

Don't worry about syncing the engines until you do a rebuild.

Ugh, that is not good news. I'm not experienced with engine repair at all. I read over the carb section in the shop manual, and none of it makes much sense to me (I'm not even sure what it means to "rebuild" them). Would it just entail taking the carbs out, cleaning them, and putting them back? Or does "rebuilding" them mean to replace the parts?

I should probably just take it to a dealer and get raped on the payment, because I definitely don't want to risk blowing the engine.

Thank you for the response

 

[dsw222]

I read as much as I could on this site about rebuilding the carbs, and I think it is something that my buddy and I can handle

I will plan on doing it in the near future... even if that is not the issue, i'm sure the boat could use a carb rebuild anyways

Thanks again for the help

 

[Dr Honda]

It's really not that hard.

Do one at a time, and keep all the parts straight, so you know where they need to go. Also... use the regular spray carb cleaner, and compressed air in each of the passages to make sure they are clear. (alternate solvent, and air)



Actually... if you can take them off, I'm just over by Irwin if you need a hand, or want me to rebuild them. (I just don't have time to take a boat in, and do the labor on the removal and install)

You can PM me. I'm free most evenings.

 

[dsw222]

Honda,

Thank you very much for the offer. I read a few guides, and feel confident that I could give it a shot myself... but if I run into problems, I may take you up on that!

I have found two kits that I could go for... two of SBT's rebuild package ( http://www.shopsbt.com/mikuni-jet-ski-carburetor-rebuild-kits/35-140.html )

SeaDoo seems to be more complete, but I'm not sure if all the extras are necessary for double the price. Also, would I need the "Accelerator pump diaphram"? And I should probably get the popoff & pump tester as well, right?

I have the 1998 shop manual because I could not find the 1997 anywhere (my boat is 97), so i will try to track down the correct manual before attempting this.

I appreciate your help through all of this!

 

[Dr Honda]

To do it right... yes you will need a pop-off tester of some kind.

I have bought from Dominic in the past, and he has good customer service.

Where ever you decide to get your kit from... make sure it has OEM (original) Mikiuni diaphragms in it. (Dominic's does) The aftermarket diaphragms suck, and normally cause hard starting issues.

You may need an accelerator pump diaphragm... it's hard to say. If you want to save a few $$$, you could take the carbs off and check them out before ordering parts. You may find that the rubber parts are still OK, and they are just plugged.

The only draw back is, if you find that you do need parts... your boat will be sitting until the parts show up. (but I guess it's sitting now because of the issues)

 

[dsw222]

Well I have an update

My buddy and I spent all of yesterday pulling both pumps to install new impellers and wear rings. We also noticed that the steering synchronization bar between the jets is bent... Apparently the previous owner backed into something... So we straightened it a bit and aligned the steering

After all that we took it out on the water. It flew! We hit 64mph (non-gps), and the biggest improvement was that the throttles were now synced. As you suggested, the left engine was probably revving wrong because of cavitation. They are alligned nicely now

The boat ran great yesterday and today. However when I was heading back to the dock, the starboard engine stalled out at max speed. I started it and it was fine for a few more mins before stalling again. When it restarted, it would not rev over 5k RPM. And it stalled again. Then it would barely start back up. When it did, if I revved over 2k RPM it would stall out. I had to set that engine to 1500 RPM to limp back to the dock using the port engine for thrust. There was also a burning smell coming from the boat

I'm very upset because the boat was running great after we put the impeller work into it. What do I do? I'm not sure what to look at, or where to start. I could put new plugs on tomorrow but I don't know if that will do anything.

Note that this is the startboard engine... The port engine was the one that was "bogging" before we swapped impellers.

Also note that I don't think its impeller related cause the starboard engine doesn't idle right after this started happening either... I need to give it 1/4 throttle to idle at 1500 RPM, and if I rev it, it will stall out

Can someone please provide insight into this?

 

[dsw222]

I also should mention... When the starboard engine idles, it makes a ticking noise now like maybe a sparking type noise, and it also seems to be backfiring occasionally too

 

[dsw222]

I swapped the spark plugs with new ones. Then I started the engine, cleaned the plugs, started it, cleaned plugs, etc for like 10 cycles... each time i did, the plugs had lots of oil on them. But finally they were coming out clean.

The boat ran after this, but that engine would not go over 5000 RPM. Under 5000 RPM, it ran identical to the other engine.

I had sprayed Bombardier Lube into the air boxes about an hour before i started having problems... i'm guessing that this caused gunk to be knocked loose and clog up the carbs even worse than they were before... so maybe the cylinders got coated with fuel/oil that couldnt be burned off which is why i kept getting oil off the plugs

So i'm keeping the boat on the trailer until i get the carbs rebuilt (which i should have done in the first place)