Hard Starting /Lost some top end after Carb Rebuild

[BMANN06]

I've noticed since my carb rebuild that i'm taking forever to start after the engines are warmed up (symptom is on both engines). Cold starting is fine, but when i swap skiers i shut down my engines as they board the swim platform when i restart i'm having to pump the throttle/choke sometime ride the starter for awhile to get them to fire. I've also noticed I've lost some top speed since the carb rebuild I used to see about 57 (dash) now hard to get to 50.

I did have a shop rebuild my carbs and they did say this is a genuine Mikuni Carb kit for my carbs. I have confirmed that the low and high screws are in the correct place according the Shop manual. Can someone maybe recommend some adjusments for me to assist in these two symptoms? I have read some other posts and didn't find an answer to my symptom so i figured i'll start a new thread.

One thing about the carb rebuild that i wasn't impressed with is the use of ZIP ties on the large fuel lines. I've heard that this is a cause for headache? This true?

Thanks a ton as usual!

 

[Dr Honda]

No... you don't use zip ties on the fuel lines. If you get air leaks... it will cause all kinds of problems. Go out and buy regular hose clamps.


OK... assuming you got the hoses tight enough... did you check the pop-off pressure? Did you change the springs? Did you check to see if your pivot arm was level with the carb body?


Just a little FYI.....


Hard starting.....

1) If you need to use the choke, and you loose top end but the engine is running smooth. Your pop-off is WAY to high, and you are running very lean on top. (be careful to not melt your engine)

2) if you have to hold the throttle half way up, and crank for a while (flooded) then your needle an seat are bleeding off. Either you have aftermarket diaphragms, your needle and seat need replaced, or your pop-off is way too low. Also... normally if you loose top speed in this scenario, the engine will almost feel like is stuttering.


Regardless... if it was running OK before the rebuild, and poorly after... the problem is with the carbs. Take them off, and do them again.

 

[BMANN06]

Thanks Doc

No... you don't use zip ties on the fuel lines. If you get air leaks... it will cause all kinds of problems. Go out and buy regular hose clamps.


OK... assuming you got the hoses tight enough... did you check the pop-off pressure? Did you change the springs? Did you check to see if your pivot arm was level with the carb body?


Just a little FYI.....


Hard starting.....

1) If you need to use the choke, and you loose top end but the engine is running smooth. Your pop-off is WAY to high, and you are running very lean on top. (be careful to not melt your engine)

2) if you have to hold the throttle half way up, and crank for a while (flooded) then your needle an seat are bleeding off. Either you have aftermarket diaphragms, your needle and seat need replaced, or your pop-off is way too low. Also... normally if you loose top speed in this scenario, the engine will almost feel like is stuttering.


Regardless... if it was running OK before the rebuild, and poorly after... the problem is with the carbs. Take them off, and do them again.

1. I'll get some proper clamps for the hoses
2. Did not check pop-off pressure
3. Not sure if springs were changed or not
4. Pivot arm is level with body
5. Engine is certainly running smooth, no studdering.

I had paid a local shop to rebuild both sets of carbs while i was installing an engine. I had two engine seizures this year so wanted rebuilt carbs in there too.

Looks like I need a mikuni manual, some carb rebuild kits, a case of beer and a saturday.

Why did i pay this shop for ??? :rant: