Help diagnosing low RPMs and no top end....

[Newbie7]

Hello! I am new here- and have a slightly odd situation. I will do my best to explain. I will say in my journey, this forum has been SO HELPFUL.

I test drove a 2005 SX230 and noticed that one engine had less power than the other. The RPMs wouldn't come above 6500 on the left engine, but the right engine was at 10k. At this point, we are only going about 30mph. The left engine also cut out once, but started right back up. The owner assured me that it was a mix of bad gas and spark plugs because it had sat for two years. I told her that I didn't feel comfortable buying it without a compression test. She said that she had other buyers, and that she couldn't wait. I asked if we could add a clause to the bill of sale stating that if it fails a compression test or mechanical review, it can be returned for a full cash refund. She agreed and signed. Now, the issue is I want to get this done in a timely manner, but the local shop is booked out two weeks. My dad is a mechanic, so we began brainstorming what could be holding this engine back. We are trying to work possibilities and solutions from cheapest to most expensive, since we don't know if we will keep the boat.

Here is a list of things that we have tried:

First up, add new gas to dilute the old gas and running it to try to burn off some of the old stuff... No change in the left engine, the right engine now only tacks 8,700. We bought the garden hose attachment and noticed that on the trailer (under no stress/load), the engines will tack 10k RPM, but not in the water. We did "burp it" to expel extra water before shutting off engines.

Second, drain all of the old gas, put in new gas, run it through on a lake test. We did get it up to 35 mph, but the RPM's only got like 200 better on each engine. Now, we are 6,700 RPM and 8,900 RPM right.

Third... compression test.... Left engine all between 175-185, right engine all between 180-190. One weird thing that we noticed is that the third cylinder in each engine has water in it. The first and second spark plugs appear to have oil on them, the third and fourth are bone dry. We also noticed that the engine cover and air filter have oil on them. The air filter was brand new (it seems), so there isn't much, but I'm sure over time there would be.

Fourth thing.... I researched on this forum like crazy and found that if there are weeds clogging it up (remember, it is new to me, so the history is unknown) it can reduce power. We commenced to getting the cleanout plugs unstuck (it took an engine hoist, WD40, some banging, and taking them apart to get them out). It is super clean underneath. No weeds. I also read that if the impeller bearing is going, it can decrease power. I checked it out, and it seems good, but I wouldn't really know what to look for- so I could be wrong.

Fifth thing, we are going to put new plugs and lake test it tomorrow to see if that helps.

If the spark plugs don't help, we were going to test the fuel pressure, but don't know how as there is no "port" to put the tester in. I would like to test the pressure before buying new fuel injectors or a new fuel pump, as that is where things start to get pricey.

I bought the boat cheaply enough that I have some money to put into it, but don't want a boat that is constantly going to need expensive fixes. If this is a small fix and just a matter of playing detective, I'm down for that. But if it is a big fix and may even result in an engine, I'd like to return, per our bill of sale agreement. The boat's interior and even exterior is in AMAZING condition, and I would hate to let it go. I really want to figure it out, even if it means throwing 1k-2k at it to get it running better.

Questions for you all:
-After reading all of this, does it seem like we missed anything? What would you do next?
-Have you experienced anything similar?
-How do I tell the difference between needing fuel injectors, fuel pumps, or spark plugs?
-How do I get the water out of the 3rd cylinder? How do I keep it from happening again? Why did it happen? I have read that it is most common in the third cylinder.
-Why won't the RPM's come up? Why can't I access the top end?
-How do we test the fuel pressure?

Any and all thoughts are greatly appreciated. I know that that was a lot to read, but I wanted to make sure that you had the whole story before spending time brainstorming.

 

[Scottintexas]

you've got a mess, I think I may pay to get a mechanic to fail it on a mechanical review for a full refund, good luck with trying to fight that out, I doubt she's going to give you the money back so you'll end up in court,

You've got to figure out what the water is in the cylinder is from, I would dry it out and run it again to see if it returns, if it does you've got a cooling line crack or corrosion leaking water into the cylinder, How much water, the plug is moist or water is spurting out when you turn it over ??

Did you drive the boat on one engine or run the hose water with the engine off ??

until you get the water figured out don't worry about anything else,

 

[Dixie Highway]

I don’t know that I’d write it off completely, but I agree you need to find the source of the water. Bad plugs will keep your RPM’s down, as will overfilled oil. How does the oil look? Milky? Dark? Too full? Oil in air filter can mean its overfilled, which could be either water adding to it or just too much added. Compression numbers look ok, I’d do a leak down as well to be sure.

 

[Newbie7]

you've got a mess, I think I may pay to get a mechanic to fail it on a mechanical review for a full refund, good luck with trying to fight that out, I doubt she's going to give you the money back so you'll end up in court,

You've got to figure out what the water is in the cylinder is from, I would dry it out and run it again to see if it returns, if it does you've got a cooling line crack or corrosion leaking water into the cylinder, How much water, the plug is moist or water is spurting out when you turn it over ??

Did you drive the boat on one engine or run the hose water with the engine off ??

until you get the water figured out don't worry about anything else,

The goal is to keep the boat hopefully, unless it is something major. I bought it at a “tinker” price point and tinker is fine as long as it isn’t major.

The cylinder actually spurted out of the cylinder during the compression test.

The left engine cut out during our lake test, which could be responsible for water in the left, but that doesn’t explain water in the 3rd cylinder on the right engine. When we ran the hose we followed the protocol we did engine on, hose on, hose off, burp, engine off.

 

[Newbie7]

I don’t know that I’d write it off completely, but I agree you need to find the source of the water. Bad plugs will keep your RPM’s down, as will overfilled oil. How does the oil look? Milky? Dark? Too full? Oil in air filter can mean its overfilled, which could be either water adding to it or just too much added. Compression numbers look ok, I’d do a leak down as well to be sure.

The oil looked good when we checked it sitting, but I’ve sense read that it should be checked after running.

Is it a traditional dipstick that I can see the range on? Can I check it on the trailer or is that not level enough? The oil definitely didn’t look like it had water in it, but I can double check tomorrow

I’m sure we can do a leak down on Monday.

 

[Dixie Highway]

Level the engine, warm it up, check it warm. I think there is a range on the dipstick, one line for H and one for L. I can’t say for sure that is proper, I have TR-1 that have a dry sump not sure MR-1 are the same.

 

[Newbie7]

I’ll check that out tomorrow. The goal is to do a lake test after drying the third cylinder and putting in new spark plugs tomorrow, and then we’ll check to see if we have more water in that cylinder.

 

[Newbie7]

Do these engines need to be burped to expel water after a lake test? Or can you just trailer and go?

 

[Dixie Highway]

It doesn’t hurt, though I believe trailering them gets the vast majority out. These engines are supposedly self draining.

 

[Scottintexas]

trailer and go, the engine is self draining but water will collect in the water box, most people "burp" at some point after running, I do it when I get home but you can never get all the water out,

You should watch the video in our FAQ section about "how the cooling water flows", it will give you some good insight,

.

 

[Newbie7]

trailer and go, the engine is self draining but water will collect in the water box, most people "burp" at some point after running, I do it when I get home but you can never get all the water out,

You should watch the video in our FAQ section about "how the cooling water flows", it will give you some good insight,

.

I’ll definitely check that out!

 

[Newbie7]

It doesn’t hurt, though I believe trailering them gets the vast majority out. These engines are supposedly self draining.

Awesome!

I’ll come back on here tomorrow after the lake test and give an update.

 

[djetok]

Do these engines need to be burped to expel water after a lake test? Or can you just trailer and go?

Trailer and go. Unless its going to be below freezing

 

[tdonoughue]

First, if there is any issue the plugs should be one of your first things to check on these engines. So that is up for tomorrow, which is good.

Folks above are exactly correct that water in a cylinder is a bad thing and you should make sure on that. How much water and how you knew it was water during the test could be important. @Dixie Highway 's questions about the oil are important, too, because they will tell if the water has gotten into the oil sump or is localized to the top of the cylinders.

Lastly, anyone who says they have a line of buyers for their 2005 and you need to buy now or move on--well, that should be a major red flag of someone trying to unload something. Your price may still be enough of a good deal to make up for it. And you have the power of this board and lots of smart folks (present author excluded) to help. Don't panic yet. Karma has a way of making the 'major engine problem' a simple matter of replacing the plugs to get a very fine boat. Let's work through it.

 

[Newbie7]

First, if there is any issue the plugs should be one of your first things to check on these engines. So that is up for tomorrow, which is good.

Folks above are exactly correct that water in a cylinder is a bad thing and you should make sure on that. How much water and how you knew it was water during the test could be important. @Dixie Highway 's questions about the oil are important, too, because they will tell if the water has gotten into the oil sump or is localized to the top of the cylinders.

Lastly, anyone who says they have a line of buyers for their 2005 and you need to buy now or move on--well, that should be a major red flag of someone trying to unload something. Your price may still be enough of a good deal to make up for it. And you have the power of this board and lots of smart folks (present author excluded) to help. Don't panic yet. Karma has a way of making the 'major engine problem' a simple matter of replacing the plugs to get a very fine boat. Let's work through it.

I appreciate your optimism and positive demeanor. This is my first boat, and at 25 on a teachers salary, a big investment for me but it was something I am passionate about.

I definitely didn’t taste the water or anything. There is a very small chance that it was actually fuel and I overlooked it. I will confirm tomorrow after checking it out.

If it is water, how do I dry it before taking it for the lake test? I’m assuming it will have to be dry dry to avoid waterlocking the engine?

I will keep you all updated tomorrow.

 

[tdonoughue]

Fuel would be more likely, of course. But please smell it rather than tasting it...

Usually if there is water in a cylinder, it got there from someone towing the boat above wake speed (or running only 1 engine and doing so). We tell folks then to pull the plugs and crank it until no more water comes out. Then run the boat hot for a good long time (like an hour) to burn off the excess water.

If the water does not go away or comes back after running, you have a bigger problem.

Edited to add: I went back to your first post. Looks like you have been running it. That is why I am doubting it is water. If it is water, you haven't been towed, so then there may be leakage from inside the engine into the cylinder. We don't want that...

 

[Newbie7]

Fuel would be more likely, of course. But please smell it rather than tasting it...

Usually if there is water in a cylinder, it got there from someone towing the boat above wake speed (or running only 1 engine and doing so). We tell folks then to pull the plugs and crank it until no more water comes out. Then run the boat hot for a good long time (like an hour) to burn off the excess water.

If the water does not go away or comes back after running, you have a bigger problem.

Edited to add: I went back to your first post. Looks like you have been running it. That is why I am doubting it is water. If it is water, you haven't been towed, so then there may be leakage from inside the engine into the cylinder. We don't want that...

Hey there! Thanks for popping on.

We haven’t towed it, but the left engine did cut out once while we were cruising and it took us a second to catch on and get it fired back up. BUT that was only the left engine that cut out and the right engine has it, too.

I haven’t taken the plugs out since our ride today, so I don’t know if the water (or potential fuel) returned into the cylinder. We will check that out on Monday.

I posted an update for everyone below, there’s more good info (and questions) there.

 

[Newbie7]

We ran it today with new plugs and a fuel injector cleaner. We got to 9,500 RPM before we all got a bath when the clean out plug blew. Thankfully it threw the hatch open, disabling the engines instead of flooding them. We sat with the bilge on for 20 minutes and then it started right up and ran smooth. We puttered around enough to heat it up and check the oil but didn’t get the RPMs way up because we didn’t trust the clean out plug. I need to buy the rebuild kits and get those straightened out next.

The oil was VERY HIGH, as many suspected on here. I think they pulled it out of storage, and just added some so it would show on the stick when sitting for viewingsWe are going to drain it and change it.

With the engine running so smoothly, is there a need to pull the plugs again and check for water/fuel in the third cylinder?

I think it is safe to say at this point that it “passes my mechanical review” and I’d like to keep it. Does anyone see anything here that indicates otherwise?

Next steps:
-rebuild clean out plugs and sand it out a bit for a better seal
-oil changes

Does anyone recommend any other next steps?

Thanks all!

 

[Scottintexas]

You only need to rebuild the plugs if they are stuck,
You need to buy some cobra locks,

Check the faq section for more info about them

 

[Newbie7]

That’s good to know! I will check it out.
I really thought we had it in there good, and then, POP goes the weasel.