Makita backpack blower died today :-(

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chuckcintron

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I have a Makita backpack blower EB7650WH which has a 4-cycle engine. Light residential use. After about 16 hours of total intermittent usage over the last year, it died today.

Upon examination, I found that one of the tiny valve lifters is gone. Probably somewhere down inside the motor now. The unit is under warranty so it will be repaired at no cost to me.

BUT...now I'm worried about it. Losing a valve lifter at 16 hours is not a normal event and I do not believe the Makita tech support guy who told me the valves were probably just out of adjustment, causing the lifter to fail early. I believe that the real reason is that the valves are probably being starved of oil. There was a slight oil slick on the valve assembly, but not 'bathed' in oil like I expected.

So my question: Do you guys think a competent repair facility will actually do the diagnostics to determine if the oil system is working right - or are they just going to repair the valve and give it back to me? How would I know for sure?

I can't have a $500 blower going through valve lifters like they are candy, especially now that the warranty is almost over.
 
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ILENGINE

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chuckcintron said:
I have a Makita backpack blower EB7650WH which has a 4-cycle engine. Light residential use. After about 16 hours of total intermittent usage over the last year, it died today.

Upon examination, I found that one of the tiny valve lifters is gone. Probably somewhere down inside the motor now. The unit is under warranty so it will be repaired at no cost to me.

BUT...now I'm worried about it. Losing a valve lifter at 16 hours is not a normal event and I do not believe the Makita tech support guy who told me the valves were probably just out of adjustment, causing the lifter to fail early. I believe that the real reason is that the valves are probably being starved of oil. There was a slight oil slick on the valve assembly, but not 'bathed' in oil like I expected.

So my question: Do you guys think a competent repair facility will actually do the diagnostics to determine if the oil system is working right - or are they just going to repair the valve and give it back to me? How would I know for sure?

I can't have a $500 blower going through valve lifters like they are candy, especially now that the warranty is almost over.
Click to expand...

Some OHV valves are lubed by oil vapor only. It doesn't take much oil to keep them going. The repairs that are done will be determined by Makita, and what the authorized service center can get them to pay for. A valve failure is not normal, and may be just a fluke. I believe the valve adjustment interval is 250 hours. I have heard of units going close to 2000 hours before wearing out. When you say valve lifter, I am assuming you are talking about the push rods, and not the rocker arms. A problem with the rocker arm requires complete head replacement per Makita.

As a Makita ASC I would most likely pull the head and examine the valve system. Would have to pull head to get to pushrods on this unit anyway. The Makita 4 stroke system doesn't use a oil pump per say, it operates on the different vacuum and pressure areas of the engine to move oil around different parts of the engine.
 
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chuckcintron

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Thanks for the reply; much appreciated. Correct -- the little push-rod has left its safe place and is now somewhere deep inside the motor :-(

May I ask - given your line of work, do you have an opinion about this blower? I did a lot of research and it got great reviews, but a failure like this - and the dependency on vacuum for oil distribution, makes me worried. Especially in NY where ambient temp can be pretty cold.

Also they say 10W-40 - do you think I should switch to a lower viscosity all-synthetic? Or will going off-script from the mfgr recommendation cause different problems?

thanks!
 
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Boobala

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NO matter, ... soon... between Gov. Cuomo, and Mayor diBlasio, with their climate-change philosophy, your gas powered blower will be banned, and you will be instructed to be a good dooby, and go electric !
 
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ILENGINE

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chuckcintron said:
Thanks for the reply; much appreciated. Correct -- the little push-rod has left its safe place and is now somewhere deep inside the motor :-(

May I ask - given your line of work, do you have an opinion about this blower? I did a lot of research and it got great reviews, but a failure like this - and the dependency on vacuum for oil distribution, makes me worried. Especially in NY where ambient temp can be pretty cold.

Also they say 10W-40 - do you think I should switch to a lower viscosity all-synthetic? Or will going off-script from the mfgr recommendation cause different problems?

thanks!
Click to expand...

Manual shows 10w-30 oil so that may help. I haven't dealt with the backpack version a lot, But I have sold some of the 4 stroke handheld blowers, and they seem to be good units. I wouldn't worry about the oil distribution. A lot of lawn mower engines use oil vapor to lube the valve train. A missing push rod could be valve out of adjustment loosing its place in the world, but seems odd that it would fail with that low of hours. Would be interesting to see what condition the push rod is in. Bent or broke. and possibly if the valve may of stuck shut momentarily causing the push rod failure The tech will have to remove the head to get to the push rods, so they can inspect everything at that point. I would be wondering were the bottom of the push rod is and if it damaged anything in the crankcase.
 
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memnon3000

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I have a similar problem. Brand new EB5300WH 4 stroke blower, bought in fall of 2020. In the spring 0f 2021, with a total of about <10hrs, it began to stall at full throttle. air filter is clean (new), i removed the fuel filter and no changes. i opened the carb, it looks clean. this thing is pristine, no clue what is going on!!
 
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ILENGINE

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Looks like you should still be under warranty with the backpack blower. I would get it to a dealer an see what they say. Could be a carb issue, but could also be a ignition module issues. I have seen more than one module do similar. Both on the chainsaws and the handheld blower. act like running out of gas, but will start back up on the first pull and will idle all day long but fail when the trigger is pulled.
 
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