Change plugs or not

[JJinSC]

I have finished Breakin of my rebuilt engine. The first tank had 50:1 premix in it. After the second tank I had the oil line nipple come out of the injector pump. I had a new oil pump and new spark plugs installed. Due to the oil pump problem and replacement I ran another tank of premixed and have now finished a tank of no premix. Should I change the plugs again at this point?

 

[El Toro 33809]

How do the plugs look? I would think if they are oily/sooty replace them. If not, happy motoring!

 

[Dr Honda]

I would keep a new set with me... but I would run on the old ones until the show an issue. But then again... plugs are cheap. If you burnt the extra pre-mix fuel... change the plugs. (but I would still keep an extra set in the ski)

 

[JJinSC]

Thanks. I'll pull them tomorrow and see what they look like.

 

[JJinSC]

Ok, I topped off my tank this mornig to declare Breakin was complete. I also dumped and cleaned out the separator/filter. I had company all day and when they left, I went to crank up the seadoo. It would not crank. After a few attempts I finally checked the separator/filter to make sure gas was pulled back in. It was. Still would not crank. Changed spark plugs. Still wouldn't crank. Held throttle wide open and it fired but didn't crank. Tried again without throttle and it would not crank. Full throttle again and it fired up and ran a little rough for a few seconds, then ran perfect.

I have cleaned the filter many times in the past and have never had this happen. This did not even happen when I changed all the fuel lines. Any ideas what caused this?

 

[Dr Honda]

No idea. It should have started... and then stumbled as the bubble is pulled threw.

Did it continue to run? If it did... and the hard start didn't happen again... I wouldn't worry about it.

 

[JJinSC]

It continued to run. I didn't run it very long because it was closing in on dark, so I put it on the dock after running up and down the river a couple times. The amazing thing is the little fumble from idle to planing off was completely gone after this incident. I'll try it out again tomorrow and see how it runs.

 

[JJinSC]

Ok. The exact same thing happened today. Cranked and cranked and it would not start. Had to hold throttle wide open to get it cranked and even after it cranked until it cleared out and ran normal. Once that was done, it ran perfect. I ran it a while and let it sit for a few minutes and tried to crank again. It cranked fine. Ran it again for a little and docked while I hooked up the trailer to the truck. When I cranked it to go to the landing after that, it cranked fine.

The only other thing I noticed is a heavy gas smell in the engine compartment.

Any ideas?

 

[Dr Honda]

It's flooding. I think your needle and seat are hanging open.

 

[JJinSC]

Ok, back to the dealer tomorrow then. That carb rebuild is still under warranty. I am also going to make sure they used makuni kits and not aftermarket. Just out of curiosity and for educational reasons, what would have caused those to suddenly start hanging so soon and and how would you correct this?

 

[Dr Honda]

I bet they used an import diaphragm. I can't tell you how many diaphragms I've changed in the past 2 years because of hard re-start issues. Last year... I put pressure on a carb... and when I tightened the diaphragm cover... the pressure releases. Basically... the bellows would push the needle arm open when the cover was tight.

I know I have some down in the garage... I'll get a pic, and post it later.

 

[JJinSC]

Cool, would like to see the pics. Very interested in how this stuff works so I can start saving money.

Get this, I took the doo to the dealer this morning and told them what it was doing. They hit the start button and it starts right up. Talk about frustration. I told them that it had failed to crank like that for the past two days. The only thing different is it was now out of water and I had turned the fuel selector switch off due to the strong gas smell in the engine compartment. He said he would keep it overnight and keep checking it with the fuel selector left on to see if it would have problems again.

 

[Dr Honda]

Yep... it's going to start when you take it to them. Did you ask what kind of parts the use??

Anyway... here the pic. The one with the red nipple is an OEM/Mikuni diaphragm. As you can see, the extra hump just outside the aluminum disk is much more shallow that the other diaphragm. (It's from a Windrosa kit) The aftermarket diaphragm was removed from a customer's carbs, by me... after the first trip out. (The local dealer did the rebuild and they came to me since the dealer couldn't "Fit them in" for at least 3 weeks)

The extra tall rib makes it push the needle open just a tiny little bit. SO... it will give you a good cold start... and it will run perfect. But, when you go to re-start, after sitting on the lake for a few minutes (like when you shut off the engine to pick up your ski/tube/wake board person) it's a bastard to restart. (The engine is flooded)

A set of OEM diaphragms fixed the problem.

Oh... and some of the import diaphragms are known to have a center nipple that is too tall. They cause the same problem, but you can file/grind it down, and make them work.

 

[JJinSC]

Thanks for the pics, doc. A noticeable difference. I called the dealer again this afternion. They waited all day with the fuel selector on and it again cranked up for them. I forgot to ask them about the carb kits. But I did look on the original invoice and it listed makuni kits. I will ask them straight out in the morning. They were going to try again in the morning to see if it would have issues.

 

[Dr Honda]

Unfortunately... it probably won't have the problem until it's hot (full running temp) If they fire it up, and kill it... then let it sit for an hour or 2... it will just fire like normal.

 

[JJinSC]

Hummmmm, each time I had the problem was when it had been sitting and hadn't been cranked in hours. After I get it cranked, It would crank fine each time I cut it off. Could this be something different?

 

[JJinSC]

Dealer called this morning and said it fired right up this morning. I am heading down there to talk with them now. Will see if I can back it into their service pond and crank while I am still there.

 

[Dr Honda]

Hummmmm, each time I had the problem was when it had been sitting and hadn't been cranked in hours. After I get it cranked, It would crank fine each time I cut it off. Could this be something different?

Yes... I may have read your original post wrong.

If it's ok on a hot re-start... then that's not the issue.

Let me know after you come back from the water.

 

[JJinSC]

Went down to the dealership at lunch and it fired right up for us again. We could not back it into their service pond as the water level was extremely low and there wasn't enough water. I got to speak directly with the technician that did all the work. He assures that he used Mikuni kits and that he insists on using all factory parts.

Hopefully, this was just a fluke, air trapped in the system or something and I won't have any more troubles. I will put it back in the water when I get home from work and try again. Any thoughts??

 

[JJinSC]

I brought it home, put it in the water and it fired right up without even having to use the choke. I ran it for a while, cut it off and it cranked right up. Did this several times. It fired up and ran great all afternoon. I am perplexed.

 

[Dr Honda]

Strange. Like you said... could have been some trapped air.

If the problem comes back... give us a yell.