1984 90HP Turns then locks up

[racerone]

???--Your measurements indicate extreme wear.--Standard bore is 3.500 "----Motor needs to be bored to make a reliable runner !

 

[ondarvr]

Take the $750 for what you were going to pay for the used motor, plus the $1000+ you'll be putting into your blown motor, sell the blown motor, add it all up and by something from this century and go boating.

 

[Faststroker383]

Sorry guys it's been awhile... I've been out of town this week for work. My bore measurements were inaccurate due to a faulty mic. Anyway, I did decide to rebuild and I ordered all the parts necessary. I will start the process of rebuilding this weekend one all the parts arrive.

 

[Faststroker383]

I got the block back together and painted up and looking good. However, I did have a question about the carbs. I took them off to clean and install new stuff but when I took the float off there was nothing attaching it to the needle. I assumed that the previous rebuild Eric left it off. I would not think this a big deal except that even with the new needle (rubber tip), it doesn't seem to fall out on its own. You have to slightly tap the carb to get the needle to fall (open). Seeing that the fuel fills from the bottom, if the needle sticks closed this could starve 2 cyclinders.

There is a clip of sorts for the needle that came with the kit but I can't seem to figure out a way to attach it to the float.

Does this carb need the needle clip or does it just function by gravity?

 

[interalian]

The clip is necessary. As you've seen, the rubber (Viton actually) tip can jam in the jet and seal it. You just need to clip the 'shepherd's crook' part around the ridge on the needle valve, then hang the needle off the float arm, then align it into the jet whilst dangling it downward, then fit the nylon pivot pin.

 

[Faztbullet]

What size was it bored too?? Did you get a different crank?

 

[daselbee]

You just need to clip the 'shepherd's crook' part around the ridge on the needle valve, then hang the needle off the float arm, then align it into the jet whilst dangling it downward, then fit the nylon pivot pin.

That's exactly what my best buddy told me about having sex the first time.......

 

[interalian]

That's exactly what my best buddy told me about having sex the first time.......

Lol... Dangle...

 

[Faststroker383]

I didn't have to Bore out the block. I was able to hone them to a near perfect finish. The same was true with the crank... I was able to polish the crank and remove all evidence of any previous damage. What is found with the crank was that nothing had grooved the crank itself. The needle bearings were smashed into the crank but after a lot of polishing I was able to bring the journals to a mirror finish and still be in spec. I did replace the pistons, rings and rod bearings as well as all new gaskets and a carb kit.

I think that it is worth noting that the entire time I have been looking for a reason that caused these issues in the first place but really haven't found anything obvious yet. The only thin that I found that I think could have been a contributing cause to the failure would have been the carb needles.

These carbs have been off before and were BOTH missing the needle spring. This ment that they were operating by gravity. The needle that came out had rubber tips so I'm sure that they could have easily gotten stuck. IF the bottom carb needle was stuck and the top carb was still working could this be enough to keep the engine tuning long enough to burn up the bottom 2 cylinder bearings?

In any case... I cleaned the carbs and installed the new needles WITH the springs and have been putting the monster back together today. I am close to being done and will post back once I am finished.

 

[Faztbullet]

Good luck and hope it stays together.I doubt the springs had anything to do with failure as gravity does not open the needles,,,fuel pressure opens them. I have rebuilt plenty that where missing. Now if they where dirty from gum/ tip swollen from E10 or groove worn in tip they could stick shut.

 

[Faststroker383]

Does anyone know what the small rubber hoses are? The diagram says they are drain lines but what are they draining? It looks to me they are all connected to a tee which is connected to the side of the intake.

 

[racerone]

They are part of a recirculation system for oil.

 

[Faststroker383]

ok so to conclude this post...
This has been a great experience working on this motor. This is the first 2 stroke that I've ever done any significant work on. Everything is back together and running like a champ. Hopefully this boat will bring many more years of fun and fishing. Thanks for all the help and for following along with me during the process. For all those out there who are inclined to tackle jobs on your own just know that all you really need to do is go slow, pay attention and use common sense. I did this entire tear down and rebuild without the help of any manual and you can too! I'm not saying that manuals aren't convenient but it can be done. Don't let other tell you that your stuff is junk. Look at it for yourself and let the facts lead you to your conclusion. If you do break it down and the facts tell you it's junk then keep tearing it down and learn something.... Life is all about learning and not being afraid to get dirty!

Have Fun!!!

PM me if you need to ask me a question. I work on LOTS of other things and am happy to share my experiences and knowledge if needed.

 

[interalian]

Good stuff! Nice to see another oldie out on the water. I did my full rebuild last year and it'll be on the lake in a few weeks too. Just need to paint it and make it purdy.

 

[Faststroker383]

I painted mine too... I wanted to be different that most so I did the Fire Engine Red block with gloss black housing and am having custom graphics made for it. It doesn't match the ugly brown boat but the motor sure will look cool.