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2001 Nissan 50 HP

2073 Views 14 Replies 4 Participants Last post by  scout
Hey Bob, I'm still having engine problems with my Nissan. I have had the compression tested and all three cylinders checked out. When the dealer/mechanic took the bottom plug out, it was wet. He said that the motor had dropped a cylinder due to trash or water in the carbs. I stripped the carbs, cleaned and soaked them in cleaner, replaced all gas with fresh gas, and it still won't idle or achieve over 4500 RPM.

The more I thought about it, I thought that since the spark plug (new as of two weeks ago) was wet, I was getting gas but not spark. I checked spark on the middle and bottom cylinders and changed out plugs between the two. Both seemed to fire OK. The bottom plug was wet this time as well. It sparked fine in the middle cylinder though. I was hoping to get no spark on the bottom and solve my problem with a new coil pack. Apparently, that isn't the problem.

Do you (or anyone else) have any suggestions or ideas as to what I might try next? I have your number. If you want me to call just let me know when. Thanks for any info you can provide. I sure do miss my boat!
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Joe, you can call me all weekend or anytime after 4:00 pm your time.
OK....I got my boat out of the shop today. It turns out that I had a bolt work loose from the plastic plates that surround the carburetors. The bolt passed through the carburetor and into the manifold. It stuck in one of the reed valves and was blowing gas rather than sucking gas. The dealer told me that I probably started out with a fuel problem and that through carelessness I probably made the situation worse. Either I didn't tighten the bolt enough or I let it fall into the manifold without realizing it (while cleaning the carburetors). Whatever happened, he told me I was fortunate that the bolt did not go past the reed valves and into the cylinder itself. He was able to pull the bolt out with a long pair of needle-nose pliers. He put new spark plugs in it, straightened out the dings in the prop, and took it to the lake for a test run. He said it was running like a champ. I'll give her a test run in a little while and see what I think.

I'm really happy to have my boat back! I'm also happy that I didn't have to sell my youngest child to pay for the repair. ;) Total cost...$101.39.

I'm BACK! :grin-big:
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Heck of a deal bro. You sure did get lucky, it's a really good thing that bolt didn't make it down into the cylinder. It sure is nice when stuff works out that cheap though. Now, if only gas was affordable enough to go to the lake as often as you'd like now that it's fixed. LOL.
Congrats old buddy. I was starting to worry about you without a boat :p .
The dealer told me that he also did some tweaking on the motor such as adjusting linkages and other minor adjustments. I tested the motor yesterday afternoon and it ran great! I was smiling like a possum eatin briars!

Thank you Bob for helping me out through this ordeal. It was really aggravating and I am glad it turned out to be not so serious.

Randall, I worry about me too. I get worse when I'm going through withdrawals! I'm back in business now though! Like Aaron said, if only I could afford gas, I'd go fishin! LOL
We're just going to have to get you a chaperone the next time you go to turning wrenches on your engine.

Good to see your back in business ;)
Hey Bob, I've been tossing around the idea of replacing my prop and have done a little research on it. I have located the Nissan prop chart and they list many sizes for my engine. I have a couple of questions though. Maybe you can clear a few things up for me.

According to the chart, my engine came equipped with a 11 X 12.4 prop. The literature I've read says that a higher pitch will provide more top end speed but less torque (hole-shot). The next higher pitched prop on the chart is a 10.2 X 13.9. Why would the diameter decrease with an increase in pitch? How much difference does a narrower prop make in performance?

I looked at a stainless steel prop (via the Nissan site) and the only one that was offered by Michigan Wheel was sized 11.75 X 17. That is a drastic increase in pitch. What are the implications of that? I think you told me once that a stainless prop would provide much better performance than aluminum. It stands to reason since there would be less flexing and less damage done when striking underwater objects. Other brands and sizes of SS props are available and vary in price. None of them are under $200. Do you have any suggestions as to which brand is superior or which to stay away from? Any other things I should consider before purchasing a new prop?

I'm hoping to increase top end speed by a little bit but want to make sure that I don't mess anything up.

Thanks for any information you can provide. I hope others can benefit from this as well.
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Joe, you can't guess at these things relating to props. It all has something to do with how well your engine will run and for how long.

A tach is required to tell you these things. Like will your engine tach out to within 200 to 300 rpms of maximum, or not over rev.

A safe bet would be to get a stainless in the same size as you have now. An aluminum will flex enough at top rpms to loose 1 pitch.

As far as diameter reducing as pitch is increased, it's all in prop engineering. They know what they're doing to gain performance.

A guy I know in Fl that runs a prop shop claims Prop Tech puts out one of the best. He says merc props are junk in comparison.

You might try taking your prop to a prop shop and getting it cupped. It's like increasing 1 pitch. See how that works before spending money on a new prop.
Thanks for the information. It is taken to heart. I sure can't afford another motor so I want to make the best of what I've got!
Keith, what about those racing boats like the Miss Budwieser? That boat's got an extremely high pitched prop and a very small diameter.

Then there's the tug boats, with montrous diameter props and a slight pitch in comparison.

Those two examples show you have your information backwards.

Pitch; The theoretical distance a prop will move forward in one revolution.
It matters nothing to me of your education, as long as you give correct info.
In this last instance you are wrong and I just proved it to the readers.

No change in props would be a definate benefit to Joe if he did it without a tach reading. Even going to a stainless in the same size is just a guess. As I said, it would be a safe bet.

Did you know that Joe's boat is rated for a motor almost twice the size he has now?

There's not much he'll be able to do. I did get his boat to plane out quicker and at lower speeds by sending him a hydrofoil for his engine. The installation is in the library. He did a great job on it.
Hey Bob as long as Joe can keep the anchor rope out of his prop he will be alright lol :p . I better watch out what I say or I may lose my boat ride when I head North lol. :crying:
You won't loose your ride, Randall. Who'd show Joe how to catch them spot tail goo's when he heads south?
You are right Bob lol. And boy does he love catching and eating those blue tip crabs :) . Looking foward to him coming south and catch some cats, I mean spotted tail goos :rolleyes: .
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