# Honda 4.5 timing belt coming off?



## akjw7 (Oct 3, 2007)

A non-running delta pressure washer with a Honda 4.5 OHV engine came into my hands recently. (model number is at home, will post if helpful later)

It had no compression when I got it. Popped the valve cover off and found the timing belt was off the cam gear. Eureka, problem identified and easily solved...or so I thought.

Eyeballed timing, fit the belt on the gear and put it back together - fired up right away and ran for about 40 seconds then quit like you turned the switch off. High fives and cheers of success quickly faded...

Pulled the cover again and found the belt off again. Did this all a second time. 

Same results, fired, ran for about 30-40 seconds, then threw the belt. 

This cam pully has no top lip (by design it looks like) - nothing at all that I can see to help keep the belt on track. I can't find a tensioner or any belt adjustment anywhere.

Any clues on why this is happening and how I can fix it?

Is it simply a stretched belt that needs to be replaced? Nothing appears damaged (belt, cam gear, etc).

Very low time engine by the way, just older.

If it requires belt replacement does anyone have a service manual section for that job they might share? 

thanks in advance - 
j


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## 30yearTech (Sep 14, 2006)

Most likely a distressed or damaged belt, there is nothing special to tension or hold the belt in place.


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## akjw7 (Oct 3, 2007)

I sure couldn't find a tensioner, guess I know why - thanks for the advice.

Now, does anyone have any advice on replacing the belt? Honda is nice enough on their website to say it never needs maintenance or replacement...but it doesn't tell me how to fix this one.

Like I said a section of repair manual would be ideal, but any tips or advice from anyone that's done this would be a big help too. 

thanks,
J


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## 30yearTech (Sep 14, 2006)

Just do a search on "timing belt" on this forum and you will see several posts with descriptions and some illustrations on how to set up the timing on your engine. 

You will have to split the case to replace the belt, there is no gasket just a high temp silicon sealant.


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## akjw7 (Oct 3, 2007)

Thanks for that. I've done that a bit and did see the one thread where you posted a few pics. Most of the timing belt issues seem to be involved with a bent crank (don't think that's me especially considering it's a pressure washer not a mower).

Those illustrations you posted in the other thread are helpful for setting timing (I roughed it by going TDC and then both valves closed, but don't know if these hondas fire on every stroke or not), 

I'm really interested more in procedures to r&r the belt. I guess it's probably just simple stuff that you really don't need a manual on, but I like to be as prepared going in as possible, so an exploded view of how the case splits and things like that would be nice. I'm sure I'll figure it out though. 

Any good parts sources that ship USPS? I refuse to pay UPS/FEDEX shipping just because I live in Alaska (personal boycot - don't get me started!) Thanks


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## 30yearTech (Sep 14, 2006)

I know what you mean, I have some relatives that live in North Pole and I sent them a care package UPS and it cost more then what I sent them.

Try jackssmallengines I think they might use usps but I am not sure.

Service manuals are hard to come by for Honda, you can find some info at the Europe site however. http://www.honda-engines-eu.com/en/welcome.html


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## akjw7 (Oct 3, 2007)

finally working on this thing

quick question - how do you position the lifters around the cam gear? I pulled the shaft for the cam gear out and with the belt thrown off the gear fell right out and I didn't get a chance to ID how it was configured. Does one go inboard towards the crank and one outboard toward the valve cover? Which one where ?(doesn't seem to be room for both on one side and I don't know if it matters which is where)

Also I found some timing setting info on the forum for a GCV160 - same for this GCV135? Thanks!


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## 30yearTech (Sep 14, 2006)

Maybe this will help.

http://www.hobbytalk.com/bbs1/attachment.php?attachmentid=49374&stc=1
GCCamIPL.pdf

Yes, the timing procedure will be the same.


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## akjw7 (Oct 3, 2007)

that was a dumb question - looked at it for a minute and it's pretty obvious both lifters go inboard of the gear....if not then the lifter is not on the valve stem! Duh...oh well!

I found the cast arrow on the crank easy - but the mark on the case is less obvious. Is this it (just to the 3 o'clock position from the hole? 

(image removed - no longer needed)

If so it appears to be bottom center - not TDC. This service manual excerpt from the honda link you gave seems to indicate TDC is here? Just want to make sure I get it right! 

(image removed - no longer needed)

Here is a wider shot of the crank arrow pointing towards what I think is the alignment mark. 

(image removed - no longer needed)

I got the part about the cam gear alignment - two marks even with the case.


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## 30yearTech (Sep 14, 2006)

No, thats not the correct mark. The mark you are looking for I believe is on the cylinder sleeve and is just a vertical line.


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## akjw7 (Oct 3, 2007)

ah - I listen after a few times! this looks like it


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## 30yearTech (Sep 14, 2006)

Yep, thats the one. Looks like you will have it back together and running in no time now.

:thumbsup:


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## akjw7 (Oct 3, 2007)

thanks very much for the great help! need some solvent to clean things up a bit - some new RTV and she'll be flying right back together. Cheers!


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## dennis leary (May 26, 2008)

Thank U For The Most Helpfull Info On The Timing Alignment Mr. Statesman Now I Know Where To Look. Thanks Again. Dennis Leary


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