RTV900 won't idle, runs above idle and stalls at idle

cobraal

New member
Hi everyone. I have a rtv900 with about 900 hours. It has run great until the other day. I went to start it and it would just crank. I pushed the accelerator pedal down and it fired right up. I left off and it as soon as the engine went to idle, it stalled out. Medium throttle or full and it runs smooth as can be with no smoke.
I first changed the fuel filter, and no change, still stalls out at idle.
I then added injector cleaner and ran it for 30 minutes and no change, still stalls out.
I put on a new mechanical fuel pump and no change, still stalls out.

Am I missing something? Any thoughts?
 
Air Filter? You run it without the air filter on? I ask about on while running because a buddy had a machine where wasps built a nest in the intake hose. He replaced the filter, no joy, it was a blocked hose. It took him a long time to figure that out.
 

cobraal

New member
I do run with both air filters. I thought they might be plugged, but while it was running with the injector cleaner, I took them off and could feel the suction. I will double check the intake tube just to make sure!
 

ovrszd

Well-known member
Have you visually inspected the injector pump to ensure the idle screw is intact?? Sounds like for whatever reason the injector pump is idling down to such a low rpm it dies??

Have you tried very slowly declining the rpm until it dies to see if you can keep it running at what would be considered a normal idle speed with a little pressure on the pedal??
 

cobraal

New member
The idle screw is still there. I have tried to lower the rpm to a "normal" speed, but it seems too high to try and get it into gear.

Do you think the injector pump is worn out?
 

ovrszd

Well-known member
The idle screw is still there. I have tried to lower the rpm to a "normal" speed, but it seems too high to try and get it into gear.

Do you think the injector pump is worn out?

No the injector pump isn't worn out.

Explain your statement above??
 

bordercollie

Gold Site Supporter
Gold Site Supporter
How old is the fuel? Do you think there could be blockage in the tank going to the fuel filter? Just wondering if the fuel flowed freely when you changed the fuel filter? Some members have had tanks with blockage down at the exit to filter. bordercollie
 

aurthuritis

Well-known member
Site Supporter
No the injector pump isn't worn out.

Explain your statement above??

yes me too. how do you know it is idling to fast? you put a tach on it? sounds like the idle limit screw needs adjusted. is the lead seal broken? has someone other than yourself been adjusting the low limit screw? what about the high limit? has it been adjusted too?
 

cobraal

New member
How old is the fuel? Do you think there could be blockage in the tank going to the fuel filter? Just wondering if the fuel flowed freely when you changed the fuel filter? Some members have had tanks with blockage down at the exit to filter. bordercollie

Fuel is new. There was fuel flow from the line when I changed out the filter. I will double check.
 

cobraal

New member
yes me too. how do you know it is idling to fast? you put a tach on it? sounds like the idle limit screw needs adjusted. is the lead seal broken? has someone other than yourself been adjusting the low limit screw? what about the high limit? has it been adjusted too?

No one has touched the idle or low limit screw. It was running perfectly for an hour or so. I parked it and shut it off. Ten minutes later, I went to start it and it wouldn't unless I held the accelerator pedal down.

I do not have a tach on it. When I try to keep the pedal depressed enough to keep the engine from stalling, the engine rpms seem too high to get it into gear without grinding.

I guess I can pull it onto the trailer and take it to the dealer. It might be the easier thing to do.
 

quid_non

Member
yes me too. how do you know it is idling to fast? you put a tach on it? sounds like the idle limit screw needs adjusted. is the lead seal broken? has someone other than yourself been adjusting the low limit screw? what about the high limit? has it been adjusted too?

Can someone direct me to where these idle adjustment screw are located - perhaps a picture if available? What's the deal with the "lead seal" = an indicator that no service tech was messing around with it??
 

cobraal

New member
Can someone direct me to where these idle adjustment screw are located - perhaps a picture if available? What's the deal with the "lead seal" = an indicator that no service tech was messing around with it??

That would be a help. I am not sure where they are. There is a wire cable through some of the bolts near the linkage. I assume they are to keep them in place?
 

ovrszd

Well-known member
I don't have a good pic of my injector pump. RTV is at the farm. I'll try to take a pic this afternoon.

The screws are on the injector pump. They control the stroke of the throttle lever on the pump. The idle screw would probably not be secured with a wire cable or lead seal. It's a maintenance adjustment. The high rpm screw would be secured and should only be adjusted by someone knowledgeable.

So look on the injector pump where your throttle cable attaches to the lever. With no pressure applied to the foot pedal the lever should be sitting against an adjustable stop screw. Loosen the locknut and thread the screw toward the lever. This will increase idle speed.
 

ovrszd

Well-known member
That would be a help. I am not sure where they are. There is a wire cable through some of the bolts near the linkage. I assume they are to keep them in place?

The wire cable is to dissuade the owner from adjusting them. The wired ones control critical functions. For example, the high rpm adjuster can be tampered with to gain more engine speed. I would imagine if you took your RTV in for warranty engine repair and the high rpm adjuster has been tampered with you may have a warranty argument or denial.
 

hondajoe

Member
No idle

Maybe you should ck shut down solenoid make sure it is not sticking some.Seems funny this happened out of the blue.The rack adjustment for idle is at the back of the pump.Also you should be able to set lever at front of pump for idle.As for running to fast to put it in gear it should go into gear at any rpm even at wide open I have mine set at 1500 rpm at idle if this helps.JOE
 

aurthuritis

Well-known member
Site Supporter
if the seals on the idle adjustments haven't been tampered with and this happened all of a sudden then i would suspect a high parasitic load that is dragging the engine down at low idle. i would suspect a charge pump failure or maybe one of the pressure relief valves might be sticking. that would cause the charge pump to have excessive pressure and would kill the engine.
 

aurthuritis

Well-known member
Site Supporter
i did some googleing and found someone had a similar problem as yours and it turned out to be the primary fuel pressure was low only at idle because the primary fuel pump would not build enough psi at idle to keep the engine running. i think the idle fuel psi should be 15 psi min. SORRY I MISSED THE PART WHERE YOU REPLACED THE PRIMARY FUEL PUMP. please disregard^^^^^^^^^
 

Alaskanassasin

Senior Member
Site Supporter
if the seals on the idle adjustments haven't been tampered with and this happened all of a sudden then i would suspect a high parasitic load that is dragging the engine down at low idle. i would suspect a charge pump failure or maybe one of the pressure relief valves might be sticking. that would cause the charge pump to have excessive pressure and would kill the engine.

Does it sound like it’s under a load? I like this logic..
 
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