Shop Discount Sea-Doo Parts

I'm gonna get this top end done soon (I hope)

Messages
39
Likes
2
Location
middle georgia
#1
I haven't completed my top end build because I still have questions.

1) My head had a lot of pitting, do I need to replace it?
2) Everyone is saying the crank is probably bad as well. I didn't pull my engine because I have no garage. I am doing the top end in ski. I read here where I might be able to get away with just cleaning out the crank. Can this be done in ski? Has anyone ever done this in ski?

Thanks.
 


Messages
8,249
Likes
223
Water Crafts
--------
#2
Generally speaking, if you had aluminum shrapnel in the crankcase as a result of a top end meltdown, it probably dusted your bearings and will be impossible to remove enough to avoid bearing failure. The crank has wear on it as well, so a double whammy.

Ask yourself "what if" the crank does fail, will you still be ahead on repair expense?

It might work, it's just riskier. Do you feel any rough or tight spots in the bearings during rotation, do they feel really loose or have a lot of play? If yes to these, odds are reduced dramatically.

Not trying to poop on your parade, just listing some thoughts and things to look for/consider.
 

AKnarrowback

Active Member
Messages
528
Likes
94
Location
Fairbanks Alaska
Water Crafts
94 xp
94 sp
94 gtx
#3
How bad did the top end fail? I have done many top ends on sleds from light seizures without going into the crank.The rule of thumb to follow is to pull the entire motor down though. If you have damage to the inside of the head then I would take it apart and confirm the crank condition, pitting in the head is a sign of chunks below.....

Sometimes the head can be saved. Not the ideal solution, but if the pitting isn't too severe a touch up with a dremmel can make things workable. It also depends on your budget, the value of the DOO (good shape or ready for a "viking funeral") and if you want a quality rebuild. I ran a pitted head in my xlt for thousands of hard miles and it never gave me trouble, I did it as an experiment. There are lots of good cheap parts on ebay, I would suggest you go that route if you don't have experience, resources, shop space etc to mess with things if using the old head causes trouble down the road.

If you put the money into the top end and ignore the bottom end then have a bearing fail then there is a good chance material will be drawn into the combustion chamber and destroy the top end you just rebuilt.

I have seen a lower end vaccumed out one time using lots of brake clean, a small rubber hose and an air compressor. It was only done because it was his race sled for Arctic Man, he burned a piston on a practice run and had to rebuild it for his race run the next day. It was a very experienced builder and he gambled the crank would last for the race, it did.

You need to pull the motor apart to be sure.
 
Last edited:

etemplet

Premium Member
Premium Member
Messages
2,531
Likes
219
Location
Louisiana
Water Crafts
1996 SPI, 1996 GTX, 1997 GTX
#4
I do mostly top ends in the skis but if the evidence is there, I replace the crank. I do what I call condition based repairs where I spend a lot of time gathering information so I can make the best decision with reliability in mind. Perfection costs about 4 times as much as reliable. I've done a lot of work over the years where equipment can't be removed and must be repaired in place and people would likely be shocked at what can be done and how long damaged equipment will continue to operate. You do the best you can with what you have including $$ to spend. I've never been a proponent of replacing everything. A good bearing is a good as new bearing and maybe better because it is worn in and happy. Leave it alone. :D :D

How many of us began a repair that just got bigger an we wish we had not messed with it in the first place. My aircraft mechanic's favorite response is... "If it ain't broke, don't fix it." That's a good way to look at things.

Good luck.
 

GGuillot

Well-Known Member
Messages
893
Likes
133
Location
Alabama
Water Crafts
1997 GTX
1996 GSX
#5
My aircraft mechanic's favorite response is... "If it ain't broke, don't fix it." That's a good way to look at things.
As a prior aircraft jet mechanic that quote is sometimes not a good way to look at things, many items that look and function perfectly fine get phase hour changed. No room for failure on an fighter jet....or aircraft for that matter.

Same thing if you're cruising out in the gulf of mexico on a PWC with an iffy crankshaft and half ass rebuild, because you wanted to save money? When doing the top end, at a minimum tear it down completely, thoroughly inspect the crank and everything else, new seals, carbs rebuilt, etc. I just replaced a crank that had only a slightly noisy inner bearing, nope not taking that chance...

"Perfection", is the only way to ensure reliability, short cuts and overlooking causes potential problems sooner than later down the road. Just my take on it..
 

AKnarrowback

Active Member
Messages
528
Likes
94
Location
Fairbanks Alaska
Water Crafts
94 xp
94 sp
94 gtx
#6
I would not skimp on rotating/reciprocating parts in a motor rebuild that I wanted to rely on or if I want it to last a long time.

I do "experiments" with questionable parts to learn. I'm doing one with my gtx knowing full well that it could have bad results, but it could actually work as well. I have the resources and back ground to fix it when the time comes.

If I only had one machine and I did not want to get left stranded or messing with it again in the near future then I wouldn't do anything less than a full take down and replace any questionable parts.
 

JeremyD615

Well-Known Member
Messages
1,086
Likes
127
Location
Nashville, TN
Water Crafts
1995 Sea Doo Speedster
1995 Sea Doo XP
1996 Sea Doo XP
#7
My aircraft mechanic's favorite response is... "If it ain't broke, don't fix it." That's a good way to look at things.
.
Where did you find this A&P mechanic? Almost everything mechanical on an aircraft should be inspected regularly and “most” would say replaced at a designated interval whether it’s broken or not. I know quite a few pilots that like to push things beyond their TBO limits, but I’ve never heard an A&P suggest it, especially one that’s signing off on your annuals...
 

etemplet

Premium Member
Premium Member
Messages
2,531
Likes
219
Location
Louisiana
Water Crafts
1996 SPI, 1996 GTX, 1997 GTX
#8
The reference was working on things that don't need to be worked on or taking a repair beyond what is needed.

On a side note, my AP/IA is one of the best in the country and my plane is one of the best maintained of it's kind... in the country. That's how Gene Rolls. :)
 

GGuillot

Well-Known Member
Messages
893
Likes
133
Location
Alabama
Water Crafts
1997 GTX
1996 GSX
#9
The reference was working on things that don't need to be worked on or taking a repair beyond what is needed.

On a side note, my AP/IA is one of the best in the country and my plane is one of the best maintained of it's kind... in the country. That's how Gene Rolls. :)
The OP is about whether or not he should rebuild only the top end or not. You brought aircraft maintenance into the fold, which one would think, especially you being a pilot, would maintain better than your own skis.

I'm sure you didn't think there would be some actual aircraft mechanics on this thead. Myself being an FAA A&P holder and prior military crewchief.

Never assume your audience is nieve about the profession your in.

Now back to the OP, is this a 951 motor? If so I'd replace the crank regardless, otherwise it's on borrowed time. All others, 787, 720, etc at least have a good look at it.

Don't just slap another top end on and call it a day. Need to find out why it pitted the head, so through look at carbs and oiling also.
 

mikidymac

Moderator
Staff member
Moderator
Messages
12,161
Likes
1,209
Location
California
Water Crafts
2003 GTI
2001 XP
1996 XP
1996 HX
1991 Superjet
2001 Superjet
#10
Ok guys, I don't think etemplet was saying you shouldn't maintain things and especially aircraft. He is just saying don't go full overboard and replace everything if there is no evidence to do it on things in general.

So let's move on.....

If the engine was just a little low on compression and the cylinder looked good but was worn out of spec then sure only doing a top end would be a normal procedure. If it was me I would still do crank seals and inspect the crank bearings.

Now with the OP, there is actual mechanical damage to the head from something letting go. As we all know on a 2-stroke the crank is directly open to the cylinders through the transfer and boost ports so if there was debris bouncing around enough to damage the head there is a really good chance it made it down into the crank and crank bearings also. If any of this debris made it to the bearings they will destroy themselves in a very short amount of time. Anytime there is a question like this with debris the crank has to come out and be carefully inspected.

If nothing else you really should be doing crank seals on a 20 year old engine anyways.
 

JeremyD615

Well-Known Member
Messages
1,086
Likes
127
Location
Nashville, TN
Water Crafts
1995 Sea Doo Speedster
1995 Sea Doo XP
1996 Sea Doo XP
#11
I didn’t mean to harp on etemplet at all... I know what he was getting at, it was just a strange statement for an actual A&P to make to a client. Usually those guys operate on a strictly by the book basis at all times, if only because of liability issues in their field...

Back to the OP’s situation, I agree. I’d at least dig in further to inspect the crank condition. I’d be really surprised if there was enough debris bouncing around in there to pit the head surface like that without some of it finding its way onto the bearing surfaces.
 

AKnarrowback

Active Member
Messages
528
Likes
94
Location
Fairbanks Alaska
Water Crafts
94 xp
94 sp
94 gtx
#13
F15radar,

We just want to see you having a running DOO that you can enjoy. It's difficult to get all the information in and out without being there and all of us would come over and help if we were in the same town.

The only way to be sure if the crank is good is to take it out and look at it.
 
Last edited:

Users who viewed this discussion (Total:0)

SPONSORED LINKS

Usergroup

Administrator Moderator Premium Member
Top