NGK BPR6es vs BPR5es

R

ruSSrt

Joined
Jan 2, 2020
Messages
225
Location
South Carolina
I was working on my Ryobi pressure washer with Honda GCV190 the other day and had to read repair manual for it. According to the manual GCV 190 requires NGK bpr5es but in pressure washer applications it needs bpr6es. I removed my plug and came to find out it's bpr5es.
I've been running that thing with "wrong" plug for over 3 years multiple hours every year. Thing is running strong, no issues (that I know of). If I get correct plug would that make any difference? Make it run smoother? More power? I ordered E3 plug for it to try it out.
Any thoughts?
 
The difference is only the heat range. For NGK's the heat range gets colder as the number gets higher. Apparently Ryobi wants a colder plug for pressure washers, probably because the engine is worked harder in that application?

Edit:
I have an E3 plug in a 36" walk behind mower because that's all the hardware store had the day I really needed it. It runs no better or worse than it did with the Champion it replaced.
 
Last edited:
ripcord said:
The difference is only the heat range. For NGK's the heat range gets colder as the number gets higher. Apparently Ryobi wants a colder plug for pressure washers, probably because the engine is worked harder in that application?
Click to expand...
Cooler plug would then "prolong" ignition/combustion? Would it make it burn cooler?
 
ruSSrt said:
Cooler plug would then "prolong" ignition/combustion? Would it make it burn cooler?
Click to expand...
No, nothing like that. A plug is "cooler" because it allows heat to transfer easier from the plug to the head. The best heat range for a plug is one that stays just hot enough to keep the plug from fouling, but not so hot that the electrodes get overheated and erode or act like a glow-plug and cause pre-ignition. It's a balancing act, really.
 
ripcord said:
No, nothing like that. A plug is "cooler" because it allows heat to transfer easier from the plug to the head. The best heat range for a plug is one that stays just hot enough to keep the plug from fouling, but not so hot that the electrodes get overheated and erode or act like a glow-plug and cause pre-ignition. It's a balancing act, really.
Click to expand...
Thank you!
 
Ripcord is right in saying the pressure washer application makes a colder plug more desirable - they run at a much higher load continuously compressing water vs, say, spinning a mower blade, etc. However, if the 5 is burning fine as you use the machine, that's ok. If the plug reads ok, it's no big deal. If you aren't sure how to read a plug, check charts online or post a picture of it.
 
That will explain this.


PXL_20201028_011815930.jpg
 
Could be too lean, is it hard to start, does the engine hunt?
Could be a bad head gasket, bad exhaust valves.
Combination of issues with high load and RPM...

Can you post a video of it starting/running?

Toro does not make engines, that's a Honda GC series, a clone fighter.
It's a pretty good engine consumer grade engine.
 
ruSSrt said:
I was working on my Ryobi pressure washer with Honda GCV190 the other day and had to read repair manual for it. According to the manual GCV 190 requires NGK bpr5es but in pressure washer applications it needs bpr6es. I removed my plug and came to find out it's bpr5es.
I've been running that thing with "wrong" plug for over 3 years multiple hours every year. Thing is running strong, no issues (that I know of). If I get correct plug would that make any difference? Make it run smoother? More power? I ordered E3 plug for it to try it out.
Any thoughts?
Click to expand...
I think that equipment manufacturers do tend to recommend a cooler plug for machines loaded towards the maximum power for most of their duty cycle. Your typical lawn mower is using very little power until it encounters tall or thick grass. A pressure washer engine is loaded towards the high end of it's range all of the time. You should favor the equipment manufacturer's recommendation over those of the engine manufacturer. They are the one's providing the warranty; they aren't going to recommend something that will increase warranty claims.
 
Zowwie! That baby is running HOT. Agree that the glowing muffler is not likely to be a spark plug issue (at least by itself). The first thing I would suspect is an exhaust valve lash that is way too tight. Or, if the engine speed surges up and down under load, you know it is too lean. It could be a combination of the two. You don't usually see sheared flywheel keys on pressure washers, as there is not a spinning blade to hit things with, so I doubt it's that.

You should get this fixed or it will shorten it's lifespan.
 
ripcord said:
Zowwie! That baby is running HOT. Agree that the glowing muffler is not likely to be a spark plug issue (at least by itself). The first thing I would suspect is an exhaust valve lash that is way too tight. Or, if the engine speed surges up and down under load, you know it is too lean. It could be a combination of the two. You don't usually see sheared flywheel keys on pressure washers, as there is not a spinning blade to hit things with, so I doubt it's that.

You should get this fixed or it will shorten it's lifespan.
Click to expand...
I don't remember seeing carb adjustment on that particular model. How do you make mixture more rich'er?
 
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