Robin Engine 500 Hour Maintenance

[BobRip]

I am at about 480 hours on my PT422 Robin Subaru Engine. (Yes, I know I have discussed this before, but could not find the posting). The recommendation is to clean the heads of carbon and adjust and check valve seats at 500 hours. I have seen some recommendations to spray water into the intake to clean carbon out. Does anyone have experience doing this? Is there a risk? Is it really effective on an air cooled engine?

I was all set to start working on the head removal. I looked at what it takes to remove the heads and it looks like you have to pull the engine to remove the intake manifold and then pull the heads. I am reluctant to do this. I don't want to be lazy and not do routine maintenance, but the engine is running great and I hate to mess with it.

Jack Robin, your comments as always would be apprecaited.

Bob Rip

 

[pajoube]

You sure have put the hours on in a very short time.
That is the first I have heard that you would remove the heads to work on them. Is everything working well? If so then I would leave it alone.
PJ

 

[BobRip]

In the back of the Service Manual it has a table for the maintenance. It says "clean heads". Maybe I have misunderstood this. Perhaps it just means clean the outside. However I got the impression from Jack Robin that this is really needed and its carbon on the inside. Let's see what others say. It also says "check and adjust valve seats" and adjust valve clearance. I will adjust the valve clearance.

I have had the machine since 2000, so that's about 100 hours a year. I do play with it a lot and help the neighbors a fair amount.

Bob Rip

 

[DHS]

I checked my 422 valve adjustment at 300 hours and they were off considerably. Adjusted to spec and the engine starts better and runs better. A couple times a year I add a few onces of Sea Foam to the gas tank. Sea Foam is suppose to help clean the carbon from two cycle engines. Since it works well in my boat motor I assume it helps remove carbon from the heads of my Robin engine.

Dale

 

[toolz_not_toyz]

</font><font color="blue" class="small">( Sea Foam is suppose to help clean the carbon from two cycle engines. )</font>

Errrr. Your PT has a 4 stroke engine. /forums/images/graemlins/smirk.gif

 

[DHS]

Errrr. Your PT has a 4 stroke engine. <font color="blue"> </font>

So, do you not believe Sea Foam can help remove carbon from a four stroke? Do you believe Sea Foam could be harmful to a fourstroke engine? I have not yet been able to definitively determine the effectiveness of Sea Foam. I have been using it for ten years in my boat, Honda four strokes and my Robin engine. I have been patiently waiting for one of them to break so I can open it up to check the carbon deposits.

Thanks

Dale

 

[BobRip]

Which is worse, sea foam or water? Thanks for having the heated discussion, so I don't have to.

And really thanks for all of the comments.

Take care, but not all of it.

Bob Rip

 

[MossRoad]

<font color="blue">I have been patiently waiting for one of them to break so I can open it up to check the carbon deposits.
</font>

If you keep taking care of them, you may never get to look inside one. /forums/images/graemlins/wink.gif

I have a 1985 Craftsman lawnmower with a 3.5HP Briggs. I have never changed the oil, air cleaner or spark plug. It still starts and runs. I just top off the oil when needed. I've been waiting for 20 years for this thing to croak so I can get a better push mower, but no luck! /forums/images/graemlins/tongue.gif

 

[DHS]

"Thanks for having the heated discussion, so I don't have to."

I certainly didn't intend to heat up the discussion. My intent was to provide alternative thoughts. Since my PT will cross 500 hours next summer I am interested to discover how others have removed carbon from their Robin heads. Since Robin has a two year warranty and my PT is four years old, I am most interested in what is necessary and what actually works.

It would be nice to have input from Jack at Robin.

MossRoad may have the secret to engine longevity. /forums/images/graemlins/wink.gif

Thanks

Dale

 

[tracdoc]

This discussion piqued my curiosity about SeaFoam. I must admit that I had never heard of it until reading this thread. On looking up the MSDS for SeaFoam, it is a mix of non-polar (hydrocarbon) and polar (water miscible) compounds: pale oil (?), naphtha (aka lighter fluid), and isopropyl alcohol (aka rubbing alcohol) in the approximate proportion of 6:3:1.

The isopropyl alcohol mixes with the hydrocarbon components because the ends of the molecule are non-polar. The polar hydroxyl group (-OH) in the middle of the molecule wets/solubilizes the carbon deposits which are then carried through the combustion process. Unlike a lot of the "snake oil" products out there, SeaFoam appears to be rationally formulated. The mfr indicates {SeaFoam website} that it can be used in 2-stroke, 4-stroke, and diesel engines, both in the fuel and in the crankcase immediately prior to an oil change.

Keeping in mind that I have no personal experience (yet) with SeaFoam, one approach might be to use a SeaFoam fuel treatment followed by a SeaFoam oil treatment, change out the oil and then do a valve clearance check/adjustment, i.e., clean out the carbon and then adjust the valves. Valve adjustment "should" be do-able by removing only the valve covers (Fig 5-39, p.39 in the pdf format Service Manual) or per the competition's guide {HERE}