Help with poor runing boat

[anthony_marquart]

It was hotter. But maybe like 83 84. Not real bad. Any input on that bearing play

 

[shoboat]

Tony,

More than a five gallons thru the motor?

I would change the bearings or you will start to wear

out the case or backplate soon if you don't. Bearings

are cheaper than a new motor or a lot of parts. Now the

5-port is hardly worth replacing many parts in the motor

because it is almost cheaper to just buy a new engine.

You have more than $225.00 in parts in that motor if you

would have to replace them all.

Enjoy Testing,

Mark Sholund

 

[rick lindow]

Anthony, if its time to change the bearings then do so! there to cheap compared to the price of a new motor (what Mark said). I plug one side of the tank and submerge it into a sink of water and watch for air bubbles, you can do this with all your tubing, pipe ect. also if you have a Boris flow meter you can pressure it up and watch your (inches h2o gauge) to see if it holds or drops in pressure indication, a great tool for troubleshooting these kind of problems. again make sure the header boot(blue seal) is good, got to have good tank pressure to assist fuel flow , you mention your needle valve O-rings, again if you have a Boris flow, pressure check it also. SORRY,TO LONG I I KNOW!!!

 

[anthony_marquart]

It probably has 4 or 5 gallons. The p/l looks fantastic so does the head button. Bearings will go in. I wish I had better way to actually tell if the bearings are causing the issue. Hate to get it back together and have the same thing happen.

 

[rick lindow]

Anthony, I run my head clearance around .006 to .008 on my .21s do you have head shims, do you know where its set at? this will also help, as stated in an earlier post.

 

[anthony_marquart]

Yep,.. it's set at .008

 

[TimothyJones]

It probably has 4 or 5 gallons. The p/l looks fantastic so does the head button. Bearings will go in. I wish I had better way to actually tell if the bearings are causing the issue. Hate to get it back together and have the same thing happen.

Thats what I did and had the same problem and I rechecked the head clearance and found it was 004". Maybe I dropped or lost a shim through all the inspection trying to find out what was going on, Just was my experience.

I assume your using the same batch of fuel as well.

 

[anthony_marquart]

Yep,.. same fuel.. Ill check the clearance when I reassemble also. I measure mine the hard way.. calipers from the top of the liner to the piston at TDC,.. then the subtract the depth of the head button,..

I never had a plug go dead while i was having this problem,.. makes me think it's not the head clearance.. but who knows.. If I do all this and still can't get it right.. Ill have to send it off to someone to look at.. The thing is,.. that damn 5P has really been a good motor.. In fact,.. I think it's pretty much just as good as the hybrid engine.. hate to see it go bad like this..

 

[David Ashcroft]

Hi Anthony just reading your first post ,I quote"

The boat would get on the pipe but never really spool up.. needle down a bit and die..

Always launched well,.. only died at a leaner needle,.. right after getting on the pipe..

To me it sounds like it needs more fuel with your prop choice and pipe length.

Short n fat

Long n lean..

And prop accordingly.

David

 

[anthony_marquart]

David,..

Well,.. I guess time will tell.. I was running the same setup that had worked well for a long time. I do prefer the short and fat method!! I also tried all the props I had.. I even tried a plastic SV27 prop.. all had the exact same performance.. The pipe is pretty short,.. but I have always run it that short,.. about 7.625,.. I am changing how the pipe is mounted for easier adjustment,..

 

[anthony_marquart]

I received the bearings. Yes the new bearings are much smoother than the old. Probably is the fix I need.

 

[Mike Larson]

Anthony.. check, maybe the crank window/case area is leaking... ie: assembled with oil, and see if theres air leaking/blowing by under pressure... I'd a parts build with the exact same needle characteristics as yours, and discovered air bubbles at closing and am testing this theory soon ( new crank, holding pressure)... i think the case tolerances wear out over time being aluminum and the case, may have done its time... idk... i normally run a longer pipe length on a sport boat also with more hull to pull around... good luck... some go... and.. well... Mike

 

[anthony_marquart]

I do think that if you let the bearings go too long the crank to case seal does go away. Fortunately this one still looks real good.. very smooth. I couldn't see any bubbles in the intake window. It has a nice POP on the on the down stroke, where the charge is compressed in the case before venting to the cylinder.

I have the motor back together,.. The new bearings are much smoother. I also found that the head clearance was was like .014,.. YIKES.. I took out a shim and got to around 8.

I have high expectations for the motor now.. we will see on Sun..

 

[Brian Sorgente]

Wow you should see a big boost in performance dropping .006". If it was running good before, its going to run a lot better now.

 

[anthony_marquart]

Yep,.. before it would run 56 mph all day.. which is not bad for a sport20 boat.. we will see,.. I have high hopes.. the motor feels better,.. it feels nice and tight again.. Compression up and new bearings, new shaft oiler keeping the shaft lubed up,.. looking forward to testing this weekend

 

[shoboat]

Tony,

How did the motor run this past weekend?

Let Us Know Please?

Mark Sholund

 

[anthony_marquart]

Hey guys,..

All is much better.. I was surprised to see the performance increase. The bearings were clearly a contributor, and I think the head clearance also.. I am not sure how I ended up with the clearance that high..

This must have been a bit of a slow decay in performance.. I think it has been a while since the boat was running as well as it is now.. But you don't really notice it when it goes away slowly and there are not other similar boats around to compare with..

Long story short, The engine lost performance from the old bearings.. the bearing were not REAL bad but I could feel the difference when I rolled the new and the old in my hands. The symptoms of low power, going lean and dieing were almost certainly caused by the bearings. So,.. if your having trouble getting you boat on the pipe,.. and it dies shortly there after, there is a good chance you have worn bearings in your motor..

 

[anthony_marquart]

Something I want to add on this topic. Sometimes it is hard for me to understand why the bearings can cause this lean condition. I think I should share my thoughts on this for some new guys to understand.

In the NR style .21 engine, and all the .12 size engines I have seen, The crank rotates in the case. As it rotates the window through the crank center opens beneath the carb and pulls the air through the carb, the fuel/air goes through the crank, through the case and into the combustion chamber. The bearings hold the crank centered in the case. The very tight alignment of the case and crank creates the seal that is needed to pull the air through the carb. When the bearing start to go bad they are not centering the crank well in the case and this causes air leaks and it can cause the crank and case to rub together. If the bearings are left so long that the sealing area on the case or the crank are damaged,.. it's pretty much junk. even when you put the new bearings in you will not have a good seal since it was damaged previously. I hate when people tell me I should spend money on an engine that is running fine. But the reality is that if you wait till your bearings actually go bad or fail before you change them,.. you probably need a new motor.. Of course drum induction and disk rotor motors are different.

At least this is what I think.