Sunstar hot engine problem

[Bb3b17j 0]

I have a Sunstar with an 18hp Kohler that runs poorly and finally quits when hot. I have found that if I pull the choke I can keep it running long enough to get back to the garage. I took the fuel pump apart but it looked ok, Fuel filter is new. Any help is appreciated.

[Al 6]

Hi, Check for clogged fins, be sure you aren't running gasahol. Check the fuel suction lines for loose clamps. This will let air mix with the fuel and the air bubbles will collect on the main jet and block it off, (vapor lock). When it cools down it will be fine. Al Eden

[Bb3b17j 0]

Didn't find any loose clamps. I am going to replace the fuel line from the filter to the pump with new clamps. I have found that with the hood off it will run twice as long. I am thinking the problem must be under the hood. Thanks for your help. Someone mentioned a possible valve problem? Is this possible with a twin cylinder?

[bud119195 119]

I have a 12 hp that i found out the carb mounting gasket was rotted and only ran on full choke .replaced the gasket and it runs fine.

[nighteye 0]

Years ago I had a Kohler 14 horse that did exactly the same thing. Al's reply above hit my problem right on the head. The cooling fins were clogged real bad. I took off all the sheetmetal and took out lots of grass and mousenests. It solved my problem. Ken

[comet66 0]

quote:

---

Originally posted by Bb3b17j
I have found that with the hood off it will run twice as long. I am thinking the problem must be under the hood.

---

Sure sounds like a cooling problem. You will be surprised to find how much stuff gets through the air intake screens on this tractor. I'd pull the shrouds off and clean them.

[ambler 0]

Mine shuts down, but my diagnosis is coil. Just goes dead after reaching a certain temp, no spark.

[Bb3b17j 0]

I had all the shrouds off and cleaned the fins this winter. Hopefully after changing the fuel lines I can use it later in the week. I am trying to remember if it started doing this AFTER I changed the filter. Could it be a bad filter?

[Ronald Hribar 91]

Filter on backwards? Crimped a fuel line? did not turn gas valve on all the way?

[Bb3b17j 0]

The arrow points to fuel pump, no visible kinks in line, no gas valve. If the weather holds out I will try to mow tomorrow with new fuel lines on.

[comet66 0]

quote:

---

Originally posted by Bb3b17j
The arrow points to fuel pump, no visible kinks in line, no gas valve. If the weather holds out I will try to mow tomorrow with new fuel lines on.

---

(Doesn't the arrow indicate the direction of flow? If so, shouldn't it point away from the pump towards the carb.?) ------------------------- The filter of course is ahead of the pump (as is mine).:p:p:p Man....I hope the rest of my day goes better than this:I:I:I

[Ronald Hribar 91]

Would also suggest to drain tank and clean. Does it have a filter inside of tank also?

[Ronald Hribar 91]

On some models, the location of gas line is critical.

[Bb3b17j 0]

Hopefully the weather will cooperate and I can try it this weekend. Thanks for all the help. I'll let you know how it goes.

[gretsch 0]

I had this happen on my Sunstar one time and all of a sudden. No fuel coming through filter. Assumed fuel pump. Got out the electric spare fuel pump and still no fuel through filter (clear for visual confirmation). Turned out to be the fuel hose end inside of the gas tank had plugged up. It has a screen on it to pre-filter the fuel so to speak. This same thing has happened on my Bobcat a few times also though it is a diesel.

[D-17_Dave 12]

If it runs for 10 minuets or so good under load and then starts cutting out youd better look at the cond. or the coil.

[ambler 0]

Mine runs a half to 3/4 hour and quits. Then no spark. definitely a module in my case. If I get my sovereign going, I'll pull it in the shop and fix it.

[Bb3b17j 0]

Great news! I just mowed for 2 1/2 hrs with no sputter. It was a cooler day and the hood was off, but this is the best it has run this year. Hopefully the fuel lines did the trick. Thanks for all the help. Have a great day!!

[MikeES 454]

Does your engine have the anit-icing kit? Is the air cleaner connected up to the "winter mode" with the snorkel pulling air off from the exhaust manifold? If so remove top of air cleaner and rotate snorkel to face the back left of the engine. This has caused many "vapor locks" on the twins.