Problem cranking a 97 XP

[yama0918]

I bought a 97 XP yesterday with a trailer and cover.

Before a paid the guy, I tried to start it. When you insert the key it beeps two times and attempts to crank but will not start. I figured his battery was low so I connected jumper cables to my truck and it still would not crank. When I removed the plugs, it will crack very fast. The compression in each cylinder is 210 so I figured the engine was good and paid $1000.

When I got it home I did some diagnostics.

1. All of the fuses are good.
2. I put in a fully charged battery which was at 12.5 volts.
3. When cranking the engine with the plugs removed, the voltage drops to about 11 volts.
4. When trying to crank with the plugs in, the voltage drops to about 7 volts.

I have tried different batteries with the same results and also cleaned the battery terminals. I am thinking that the starter may be bad.

Any thoughts on what I can check or what you think the problem may be? I don’t want to buy a starter just to find out that is not the problem.

 

[timmyboy76]

hey stud, think first step, is redue the compression, thats up there, man. 150ish is perfect. Might have some mods to the ski you unaware of??? You can check all grounds/cables for corrosion/burnt...

 

[seadoosnipe]

Compression?.....

:agree: with timmy on that one. A new engine turns out about 150 psi.

You don't say whether or not you are getting spark at the plugs when you are trying to crank it.

The two beeps signal that you have the correct DESS and it's ready to start.

Jumping? Did you try and jump this ski with the truck running? If so, there is a probability that you blew out the MPEM (multi purpose electronic module). This is a pretty costly item to replace.

 

[Dennis]

Cranking

What they said.
DAWG

 

[PWCdoc]

I agree on that compression. Beyond that, pull the spark plug boots off the wires and trim back until you see sufficient strands of wiring. It's a common problem on Doos for the wire ends to burn down after a bit of use. Try that, check for spark...then fuel of course...and let us know what you get.

 

[yama0918]

I spoke to the guy I bought the ski from. He did not do any modifications to the engine but the compression was at 200 lbs per cylinder when he bought it. He said that he charged the battery about three months ago and it started right up. At some time in the past he installed a new high performance starter. I looked at the starter and it is an Aqua Torque.

That is a good idea to trim the spark plug wires. However, I am getting spark from both plugs. My first concern is to get the engine to turn over with the plugs installed.

I decided to unbolt the top end to look inside and take some pictures.


This is with the cover removed.

With the rear piston at top. It is a little oily.

With the front piston at top. It has a carbon buildup on it.

This is a close up of the number on the piston. The number is 81.89 which is the size of the stock pistons. This leads me to believe that the engine was not modified.

 

[PWCdoc]

Front cylinder looks like it's running rich and that head looks like it's been reworked...and not very cleanly I might add. You might want to consider getting a stock head.

 

[yama0918]

Is the head you are referring to the last picture? The part number stamped on it is 923 300. The parts catalog shows it as 923 301.

Why do you say it is not a stock head? Does it look like it was modified or changed?

If you think the head is causing the problem of high compression, then I'll look to replace it.

 

[PWCdoc]

Yes, the last picture. You can see the machining marks on the squish band which is the outtermost circumference of the dome area. It almost looks like an SBT job but hard to tell from the angle you took the photo. That and SBT machines the heads to actually lower the compression rather than increase to what you are getting.

 

[scooper77515]

How can you machine the heads to reduce compression?

If you take anything off, you will increase compression ratio. Unless you put in a thicker head gasket (car talk, here).

 

[PWCdoc]

No, only if you mill the head to physically make the top closer to the top of the cylinder with you increase compression.

Redesigning the squish band is completely different and is not milled as you may be thinking but rather in a circular manner. Look at the machining marks on the squish band on the head...last picture. That is not a stock head design. It may have been milled initially but then they had to rework the squish. A properly designed squish band is extremely important to getting the most out of your motor. Do not assume all head designs (combustion dome)are the same and will net you the same performance.

If you do not mill the head and just remove material from the inside of the dome area, you will lower the compression ratio. Is that about a '72 Ford Maverick I see in your avatar?

 

[yama0918]

Here are some closer pictures of the head. If this head is causing the high compression, do I need to replace it or can this one be fixed?

Does anyone have a picture of what the head should look like?

 

[PWCdoc]

Yes, I think youneed to replace that head. It looks like it has been milled and then the squish band was reworked so it would not hit the head. Measuring the squish thickness would tell us more. But I'd be willing to be that the profile of the squish is not proper. I could draw something on paper to give you a better idea of what I'm talking about. But I think anyone here that builds motors will agree that that head looks tweaked (maybe too much) and 200# is too much compression for you. Also, it looks like the front and rear cylinder were not running the same.

 

[Dennis]

Compression

By chance does this engine have oil in the bottom of the cases that is coming up on top of the pistons when cranking causing high compression?
Engines that sit for along time without being started will do this.
Cylinder head domes look real oily!!
Sure your gauge is accurate?
Does the engine rotate easily by hand with the spark plugs out?
DAWG

 

[scooper77515]

GREAT closeup pictures:cheers:Too bad I cannot help with the technical aspects in this case.

It is a 74 Maverick with the big bumpers swapped out with the earlier 72 bumpers. Check out my website to see what I have been doing with it over the years...http://home.cmaaccess.com/~scodon/

 

[yama0918]

I purchased a replacement head and will let you know the results in a few days when I install it. Does anyone have a recommendation on the best way to clean the tops of the pistons?

I am not going to touch the carbs until after I get it to start.

 

[PWCdoc]

I purchased a replacement head and will let you know the results in a few days when I install it. Does anyone have a recommendation on the best way to clean the tops of the pistons?

I am not going to touch the carbs until after I get it to start.

The best is to do it before you get it started. I'm willing to bet that if it does run, it won't be long before you stick one of those pistons. You're in there already...might as well check the carbs out and rebuild them if necessary.

I'm giving you free advice here on how to prevent potentially learning an expensive lesson.

 

[yama0918]

I just don't want to compound the starting issue. After I get it started with the new head, I'll check the carbs immediately after that.

 

[Nate Surveyor]

If I still has the gray fuel lines, they could be at the root of a number of clogged fuel system troubles. So, let me know if it still has them, and I can post back the rest of this story.

Nate

 

[yama0918]

I just looked and all of the fuel lines are gray.

 

[seadoosnipe]

Stock or modified?

In my opinion, everything in your pictures look as if they are stock. PWCdoc sounds like a very, very knowledgeable mechanic but there are a few things missing from this scenario. First, the pics you took, which are excellent in you trying to find answers, show definite signs of detonation. Detonation (where the piston and head look as if they had a bunch of BB’s inside while the engine was running) is caused from many things. In your case, it appears that it’s caused from your carbs either being out of sync with each other or your high and low speed jets are not adjusted equally. There are other causes, such as your water injection system not working properly but I’m betting on your carbs for this one. Google the word “detonation” and you should find some nice pix along with explanations.


Before I disagree with PWCdoc about your heads being modified or turned down, causing your higher compression, I think a volume test should be done first. This is the only true way to find if this has taken place. If after this test, the volume area is less than stock, then I’ll be in agreement with PWCdoc. But, from what I see, I don't see visible signs of any aftermarket work.


To do this test, you’ll need a 50 mil graduated cylinder (a 0-50cc capacity burette would be much easier but more expensive to come by). If you don’t have one of these, you may be able to find one where lab equipment is sold. The graduated cylinder is precise, so it’s important that you find one. You may even find one at a local auto parts shop. You can also look to a pharmacy for a syringe (not the ones with the needles on them) that's measured in CC's.


To do this test, your engine will need to be cold. This test will measure the region of the cylinder head that is above the piston at TDC (top dead center). The head and gaskets must be on and tightened to their proper torque specifications. Both spark plugs removed.
Bring one piston to TDC using a top dead center gage (I use a wooden pencil. If you practice, you’ll now when your at TCD). Now, using a 50/50 mix of your gasoline and oil mix, slowly fill the dome of the compression chamber with the mixture. You’ll need to do this slowly and as soon as you see liquid at the top of the spark plug holes, stop pouring in the liquid. The liquid level must not drop for a few seconds. If it does, there is a leak between the piston and cylinder. The spark plug depth of the BR7 and 8 ES plugs have a depth of 19mm.


So, now, mark the calibrated cylinder (graduated or burette) and see how much liquid you put in. A stock engines volume capacity at stock is 2.25cc with the included depth of the spark plug threads.


Check the other piston using the same procedure. This will in fact tell you if the head has been machined to give you a lower volume in the combustion chamber, creating a bit more compression. But you should never see 200 PSI. Do the compression test again at some point. I’m very curious as to why your coming up with such high readings. If you still get anything greater than 160 or 170, take that compression gage and do one of the cylinders of your car or lawnmower engine. Post the results from that test along with the engine size and make. The possibility of your gage being bad always exists.


Sorry for such a long post but your time and effort into taking the engine apart and trying to find a solution to your problem tells me that you’d like all the best info you can possibly find, so, here it is.:cheers:

Definition of "detonation"........ http://en.wikipedia.org/wiki/Detonation

Information on what causes detonation..... http://www.misterfixit.com/deton.htm

I've also got a few pix of pistons that show signs of detonation, running lean and what one looks like that is in good condition. I see the headers for the pix didnt' come thru so, the first three are signs of detonation, the 4th one is running lean and the last pix is one that is running in good condition.

 

[nswillin]

Nice post Louis! :hurray: Only thing I might add is you can get the big syringes at the farmers CO-OP, most towns have one, at least in the South. They use them on live stock or what not. We get them all the time for different tests on our turf equipment at the golf course. :cheers:

 

[yama0918]

I was in the process of bolting on the old head to do the volume test as suggested by seadoosnipe. Then my door bell rang and my replacement head arrived. There was a definite difference between the heads. The new head was thicker and it was now easy to see how the old head was ground down.

Instead of continuing to do the volume test I installed the new head with anticipation of checking the compression. Magic - The compression in each cylinder is now 148 pounds.

When I put the plugs back in, it again would not crank. I removed the battery and charged it for a couple of hours. With the battery now reading 13 volts, I installed it and the engine would sometimes crank with the plugs installed. That is a lot better than it ever did. I connected the plug wires and shot some starter fluid in the carbs. (I know that you should not use starter fluid but I just wanted to do a quick test). To my surprise, it started and I ran it for five seconds before tuning it off.

The next step will be to remove and clean or rebuild the carbs as necessary. I will also replace all of the gray fuel lines.

Since it sometimes will turn over and other times not, do you think I still may have a battery or starter issue? This same battery has no problem starting my other ski.


Here of pictures of both heads for comparison

 

[scooper77515]

WOW!!!

I couldn't see the difference in the first pictures, but the second set of close-ups really shows the work that has been done.

It is amazing how much a little machining will affect your engine.

Glad it is running for you now :hurray:

 

[PWCdoc]

Told ya on that head. :^) You know immediately after you've seen enough of them. Now, on the carb issue..check those out and let us know. The first thing I'd check is where they are currently set and see where they compare to stock settings. I don't have my manual in front of me at the moment but I'm sure someone here has the settings available. OEM settings...not the "this is what I run" settings.

Detonation? MMmmmmm....can't say that for sure without having the parts in my hand but I'm leaning more towards carbs not metering fuel properly. The settings are going to be off...wrong jets...something is not as it should be.

Difficult to turn over? Check all of your connections. Also, since you will have your carbs off you might as well take out the starter since the carbs are going to be out of the way and will make it easier for you. What I'm thinking is that the contacts on the armature on the inside are dirty or worn down and not making adequate contact to give your starter the current it requires to turn the motor over. Check all your connections first. I've also seen the groung cables to be the issue. You could check that by other methods. Also, it may be your starter relay. If you want, let me know and I'll walk you through that checking to isolate it down to the faulty part.

And when you CC the combustion cambers on the heads, you do that with the head removed. Filling the cylinder with fuel will only cause your cases to have fuel puddle up because the rings are not designed to be liquid tight enough to trap the fluid to give you the proper reading. Now, if you put grease along the outter perimeter of the piston so the fuel won't leak past the rings then you could get a reading but the dimensions given for heads is typically by measuring on a bench, head removed and sealed up to compare to stock volume range. You could have measured your stock squish thickness with the head on but that'd only give you the thickness of the squish, not the volume of the dome itself.