Robin DY35 Starting Issues

Engine's, injection, valve's, timing, crank's etc..

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brucey
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Robin DY35 Starting Issues

Post by brucey » Thu Dec 19, 2013 8:48 am

I have just purchased a Robin DY35 Engine to put in a jet wash (I want to use the electric start Robin DY41 engine currently fitted to the jetwash for my Robin Enfield project).

The DY35 hasn't been started for a number of years (I think there is a date stamp on the injector which says 2001). Overall, the engine appears to be in good condition with no leaks or rust. I was told it had very little use before it was removed from a piece of development farm machinary some years ago.

I changed the engine oil (which was sludge), put on a spare (new) DY42 tank and Chinese Fuel tap/filter assembly (both were missing) and pull started it in my shed. It started after a few pulls but I switched it off after about 5 seconds as that's how long it took to fill my shed with smoke!

I made a stand and wheeled it outside to give it a longer run. I put a small amount of injector cleaner in the fuel but apart from a 2 second burst cannot get it to resart.

I have tried squirting easy start into the air cleaner which seems to make it pop a bit but not run.
I checked the valve clearances which appeared to be neaerer 1mm than the recommended 0.1mm in the book, so I adjusted them.
I removed the pipe to the injector and get small dribbles of fuel pulsing from the end of the pipe when I pull the starter.
I swapped the injector with the one from my DY42 engine (which runs) and tried starting it again without success.
Then I gave up because I was too knackered!

If I attach the original injector to the fuel line and pull the starter, should I see fuel squirting out the end?

I was going to try replacing the fuel pump with the one from my DY42 engine next.

Does anyone have any ideas? I'm new to working on this type of engine so may be missing something obvious. I have turned the fuel on though!

Looking on the bright side, I'm bulding up my Right Arm mussles niceley!

Any advice would be appreciated.

brucey

gilburton
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Re: Robin DY35 Starting Issues

Post by gilburton » Thu Dec 19, 2013 9:36 am

Refit DY 35 parts.
Don't remove injector just yet.
Are you getting a decent flow from the tank,under gravity, before and after the filter?? Has the aftermarket filter got a bleed screw?? If the flow is not brilliant through the filter you can pressurise it by putting your mouth over the tank filler. Is the filter vertical?? Any air trapped in the filter??
Now reattach the injector pipe and tighten it up. If you don't tighten it you will suck air in!!.
Crack open the bleed screw on the pump until you get a good air free dribble, under gravity, then tighten up.
Now just crack open the injector pipe at the injector end. Don't remove it just quarter/ half a turn from tight and pull starter until fuel appears then tighten it up.
It should now start if the fuel supply is the problem??
Has it got a decompresser on the rocker cover??
While bleeding open throttle fully.
My engine had 2 control levers. One was the throttle and the other the stop.
If yours only has one are you setting the throttle at the starting position?? i.e. full throttle.

brucey
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Re: Robin DY35 Starting Issues

Post by brucey » Thu Dec 19, 2013 12:08 pm

Thanks Gilburton,

I have already done most of what you said but will double check and do it again.
I will also replace the original DY35 injector and bleed the fuel system.

I'm a bit worried I wasn't getting a bit more action from a shot of easy start in to the air intake as I thought no diesel could resist this! (it also bypasses the whole fuel system!).

The fact that it did start and run until I turned it off (using the throttle/stop lever) is encouraging.

If it doesn't go after 5 pulls, I have to go and have a cup of tea......I must be getting old!

brucey.

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Re: Robin DY35 Starting Issues

Post by gilburton » Thu Dec 19, 2013 12:32 pm

I still suspect poor fuel supply/air. The engines are quite simple.
If you don't remove all the air it will just compress and all the pulling on the starter won't help.
If you eventually decide to remove the injector follow the bleed procedure again but turn the injector pipe and injector to an angle so that you can insert it in to a bottle for safety and see the spray.
I know these don't have the same pressure as a car type system but you don't want it in your eye!!
You are finding compression before pulling the starter ??
It's a bit like kick starting an old single.

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Re: Robin DY35 Starting Issues

Post by Stuart » Thu Dec 19, 2013 3:13 pm

I've kicked a bike over with an injector hanging out. You should get a party balloon size blast of fuel vapour from the injector. Don't get anywhere near it otherwise amputations will be the next thing on your to do list!

I've had air getting sucked in at loose joints causing loss of power (& less fuel to injector) & weirdest of all, plunger pin within electric cut off solenoid broke free & was drawn to cut fuel every time bike was kicked over.
Maybe renew pipes all round to injector if you're sure the injector needle isn't sticking.
Stuart. M1030M1, Honda NC700S, Grom!, Toyota Corolla 1.4 Turbo Diesel. Favouring MPG over MPH.

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Re: Robin DY35 Starting Issues

Post by brucey » Thu Dec 19, 2013 7:32 pm

Just an update:

I refitted the original injector. Before putting it back into the engine, I inverted it and put a drinks bottle over the top. When I pull the starter, I get 4 jets of high pressure fuel squirting out equally spaced.

Upon refitting, I kept the injector fuel nut slightly loose and turned the engine over until fuel came out the union. I then retightened it.

The engine still doesn't start. I can see exhaust fumes and it will run for several seconds if I squirt easy start into the air cleaner now. I haven't tried continually squirting easy start as it tends to make it knock and proves nothing.

I'm pretty sure there is no air in the fuel system (I used see through fuel hose from the tank to the pump). I'm assuming I have the fuel filter plumbed in the right way (if there is a right way) with the fuel tap on the inlet side.

I guess the next thing to do is fit the fuel filter from another engine to make sure I'm getting enough flow (it did take quite a long time to fill up the filter bowel even with the pump bleed screw open).

After that I suppose it could be stuck governors and bob weights.

I'll give my arm the rest of the night off!

brucey

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Re: Robin DY35 Starting Issues

Post by alexanderfoti » Thu Dec 19, 2013 7:57 pm

I was going to agree with AIR in the system. Your problems sound very much the same as mine. Air issues where a real pain. I basically followed the fuel up the pipe, undoing each union until I saw fuel and then did it up. It still ran like crap for a while until all the air was expelled.

Maybe you have a duff fuel pump?

Fuel flow shouldnt be an issue unless you have a high demand or a TINY fuel filter. When its being started, does it attempt to start at all, or completely dead?

If its starting a little bit then I will look at the goverener as you say, to see if its stuck.

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Re: Robin DY35 Starting Issues

Post by brucey » Fri Dec 27, 2013 7:20 pm

Had another go at starting the DY35 today.
I checked the fuel supply and found only a very slow flow into the pump. I then decided not to be quite so tight and fill the tank up (well 1/2 fill the tank). That immediately increased the fuel flow!

I remounted the engine to my test bench and started it with a little help from Mr Easy Start :D

I thought I had it cracked but it died after about 20 secs and is back to giving fuel starvation symptoms :( I can get it popping and running for very short periods but nothing longer than a few seconds. I'm beginning to wonder if this is why the engine was removed in the first place!

If I have a good flow to the pump, is it worth stripping the fuel pump? What would I look for? I guess I could start swapping bits from one of my other 2 Robin DY 41 and 42 engines which both run fine.

Any advice appreciated.

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Re: Robin DY35 Starting Issues

Post by coachgeo » Sat Dec 28, 2013 3:36 am

Start with simple stuff. Sounds like as the engine gets going the vacuum from the pump builds enough vacuum to start pulling air in from some place.

Try running it from a fuel can to see if there is a leak between tank and fuel pump.

On this model is the IP and the fuel pump all in one? Another words is there a pump to move fuel from tank to IP or not?

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Re: Robin DY35 Starting Issues

Post by gilburton » Sat Dec 28, 2013 9:09 am

Possibly your aftermarket filter/tap is not letting enough fuel through so after your initial bleeding/setting up a good flow it runs until it uses up the fuel in the line then struggles again??
Using a genuine filter/tap once bled the fuel should literally pour out of the bleed screw on the pump, by gravity, assuming all the air is out of the glass bowl.
Just turn on the fuel then loosen the bleed screw on the pump. If no fuel comes out within a few seconds the filter is the problem. No need to physically do any bleeding the fuel should flow by gravity!!
Once happy with the flow tighten up and bleed the injector.
I had this sort of trouble using the cheap in line plastic disposable filters you can buy in bulk.
They just weren't letting enough fuel through possibly they were too small or petrol ones don't suit diesel??
Assuming it's letting fuel through,no air is getting in and it's pumping fuel to the injector it should run??
You do have copper washers on the banjo joint on the pump??
Is there an arrow on your aftermarket filter or can you put the link up if bought on ebay??

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Re: Robin DY35 Starting Issues

Post by brucey » Sat Dec 28, 2013 10:30 am

http://www.ebay.co.uk/itm/221329913683? ... 1439.l2649

It appeared to allow enough diesel to flow once I had filled the tank up but I think it is designed for a smaller diesel generator. Before I get too carried away, I'll use one of the genuine Robin Filters to see what happens.

Looking on the bright side. 20 secs running proves it isn't a number of other things and that's the longest so far!

brucey

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Re: Robin DY35 Starting Issues

Post by gilburton » Sat Dec 28, 2013 11:12 am

Am I right in thinking the "angled" connection behind the tap is the inlet which fills the bowl "outside" the filter and the other straight one is the feed to the pump from "inside" the filter?
Looks large enough to me.
Yes you are correct re the running that's why I still suspect a fuel flow or air problem :)

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Re: Robin DY35 Starting Issues

Post by brucey » Sat Dec 28, 2013 1:00 pm

DY35 Filter.JPG
Chinese Fuel Filter Arrangement

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Re: Robin DY35 Starting Issues

Post by coachgeo » Sat Dec 28, 2013 1:35 pm

Since this is a glass bowl.....

Prime and start her up.

What goes on in the glass bowl? Lots of bubbles? Does it begin to fill with more air than fuel?

Before it conks out....... remove the fuel cap off the tank and see what happens.

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Re: Robin DY35 Starting Issues

Post by alexanderfoti » Sat Dec 28, 2013 3:28 pm

gilburton wrote:Am I right in thinking the "angled" connection behind the tap is the inlet which fills the bowl "outside" the filter and the other straight one is the feed to the pump from "inside" the filter?
Looks large enough to me.
Yes you are correct re the running that's why I still suspect a fuel flow or air problem :)
Yup thats right, the one in the center is the engine connection, one on the oustide fills the filter from the outside.

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Re: Robin DY35 Starting Issues

Post by Eddy Wane » Sat Dec 28, 2013 4:03 pm

Been watching this topic for a while. I hope you sort out the motor, if it helps I found this site Stateside.

http://www.jackssmallengines.com/

If you click on the Robin logo that page will bring up a engine tab which has manuals as PDF's.

Eddy.
Building the bike. Top of my list, bottom of the wife's.

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Re: Robin DY35 Starting Issues

Post by brucey » Sat Dec 28, 2013 6:07 pm

Thanks guys. I'm sure I'll get there in the end!

The manual contains far more information than my existing one (I'll be printing it off when I get back to work!)

It's also nice to get confirmation that I haven't made a silly mistake like putting the fuel pipes on the wrong way around.

I have to be careful when I start it as the neighbours complain at anything after midnight!

I only wanted to fit it to the jet wash so I could liberate the electric start Robin DY 41 engine currently fitted to it. I'll keep you posted.

Thanks again,

Bruce.

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Re: Robin DY35 Starting Issues

Post by Eddy Wane » Sat Dec 28, 2013 6:32 pm

Hi Bruce.
Comparing the picture of your engine with the PDF on the web site there does appear to be a difference but that may be cosmetic and the functionality of the engine is the same.
Eddy.
Building the bike. Top of my list, bottom of the wife's.

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Re: Robin DY35 Starting Issues

Post by brucey » Sun Jan 05, 2014 11:34 pm

Happy new year to you all :D

Just an update:
I took the Robin fuel filter assembly and hoses from my DY42 engine (that I know runs o.k.) and fitted them to the DY35. When I loosened the bleed screw on the pump inlet, I got significantly more flow coming through when compared with the ebay fuel filter.
Long story short, It fired up and ran beautifully for at least 5 mins (the neighbours started twitching their curtains so I turned it off) It hunts a bit on the slow speed setting but I'm sure it just needs adjusting. So even though there appears to be sufficient flow coming out of the pipe with the ebay fuel filter fitted, it isn't quite enough to allow the engine to run. Lesson learnt. Buy cheap, buy twice. Now I've got to find another fuel filter :oops:

Still chuffed I've managed to get all 3 Robin engines running. I need to check the speed of the DY35 before fitting it to the jetwash. Even though it has a reduction box fitted, the 'D' suggests it's a 3000 rpm output and I think I need 1500rpm to run the jetwash. Maybe the gears can be swapped from the DY41B currently fitted to the jetwash.

I then need to build an electric start DY42 engine using the DY41 jetwash engine and the pull start DY42 sitting on my bench.

I'm also still looking for a suitable Enfield Bullet to convert.

At least I'm making some progress even if it is a bit slow.

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Re: Robin DY35 Starting Issues

Post by coachgeo » Mon Jan 06, 2014 1:49 am

brucey wrote:Happy new year to you all :D

.... I've managed to get all 3 Robin engines running.
Congratulations on getting them running

I need to check the speed of the DY35 before fitting it to the jetwash. Even though it has a reduction box fitted, the 'D' suggests it's a 3000 rpm output and I think I need 1500rpm to run the jetwash. Maybe the gears can be swapped from the DY41B currently fitted to the jetwash. ....
The 1500 pumper could have completely different injection pump fuel system from your 3000 pumper. the 1500 one likely has the IP is tuned way down from the factory. Also could have very different form of governor /accelerator etc. Thats what keeps her at 1500 steady. Now you 3000 ???? not sure its original intended design. If it is designed to be constant speed 3000 rpm; and many industrial engines are; It well could have something conceptually similar or be a good bit different in how the accelerator/governor works... For sure the IP is tuned completely different allowing for the higher RPM's to be reached. Injectors may be different between the two as well.

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Re: Robin DY35 Starting Issues

Post by brucey » Mon Jan 13, 2014 8:22 am

Just to close this thread, I'm pretty sure I have identified the cause of my problems.
I stripped the new (Chinese) fuel filter assembly as it appeared the flow was at least 50% less than the original Robin fuel filter I fitted. I found the rubber seal in the fuel tap partly blocking the fuel passage. (See photo). I cut the hole to the correct profile (to give full flow when the fuel is turned on) and re fitted the assembly.

When I undid the bleed screw on top of the fuel pump union, the fuel gushed out. When I originally fitted the filter, it just about trickled out. Maybe that would have been a good time to check the seal! Just because something is new, doesn't mean it's not faulty!

I have now started the engine and it runs fine :D Infact, I've slowed the full speed down on the throttle stop and increased the slow running speed as it was hunting slightly. It now runs and ticks over beautifully. 8)

I will run it for around 20 mins (during the day) and with some injector cleaner in the fuel then change the oil again as the original stuff I took out was a bit 'sludgey'.

Lessons learnt (at 55 years old!). Start with the obvious!

Yet again, for an engine that's probably been sitting around for well over 5 years (probably nearer 10), I'm amazed how diesels start and run (once you get enough fuel going in!).

Thanks for all your advice and support. I now have 3 running Robin diesel engines. Should I try and get them all going at the same time? :lol: I'd better start looking for a suitable Enfield again.
Fuel Filter.jpg
Fuel Filter Housing (blocked)

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