2001 gti starts on trailer and not in the water

[Cheflen]

So I got a good compression test, both cylinders are at 138 exactly, perfectly even. This is with a cold motor and it still hasn't been broken in. So now I'm not sure what the problem is, luckily I don't need a top end. The plugs are still covered in oil, I haven't run out the tank from last year with the stabil so maybe I should flush the tank? I also have oil mixed in with the gas. Any ideas would help

Also forgot to hold the throttle open during the test so it might even have more compression than that

 

[Cheflen]

I really need some help here the compression results were good both cylinders were 138 so I'm not sure what the problem is it seems to be running very rich

 

[Cheflen]

Need to know your compression number.
Off timed rotary valve would affect the numbers but would still build up slowly.
To much gap or wear wouldn't hinder the compression but yes hard to start.

Air leak maybe.
Off timed valve, how did you end up after setting it ? About 1/2 inch below the mag port ?
ignition timing off, did you replace the outer crank seals?
Did you do anything to the carb ?
Does it have an accell pump or not?
What is your idle set to? 3k out of water?


Need some more info.
And maybe a video.

Would ignition timing be a cause of this? I know I just put everything back together as I saw it before but I'm not sure if I put the ignition timing back properly. It did run fine in the water when it started up though.

 

[Dr Honda]

Would ignition timing be a cause of this? I know I just put everything back together as I saw it before but I'm not sure if I put the ignition timing back properly. It did run fine in the water when it started up though.

Would ignition timing be a cause of this? I know I just put everything back together as I saw it before but I'm not sure if I put the ignition timing back properly. It did run fine in the water when it started up though.

It could. Your compression is low for a fresh engine... but it's in the running range. At this point... start at the beginning. Check the Squash band, Check ignition timing, check rotary valve clearance. If fuel is suspect... drain it, and replace. Since it's a fresh engine, you still need a little oil in the fuel.


Oh... verify that your oil pump is set right. It's possible for the arm to flip all the way around, and give full oil. That will kill plugs at idle.

 

[Cheflen]

It could. Your compression is low for a fresh engine... but it's in the running range. At this point... start at the beginning. Check the Squash band, Check ignition timing, check rotary valve clearance. If fuel is suspect... drain it, and replace. Since it's a fresh engine, you still need a little oil in the fuel.


Oh... verify that your oil pump is set right. It's possible for the arm to flip all the way around, and give full oil. That will kill plugs at idle.

How can I verify the pump setting, I know that the arm is supposed to be facing down because I have had it flip out on me but I'm not sure if it's in the right spot now.

 

[Cheflen]

Another update, I took it out today, started on the trailer after a few cranks, ran great on the water. I drove it around for about 20 minutes staying under half throttle and everything was good. I noticed that if I let it idle for a little bit before I shut it off it would be hard to start, but if I gave it a lot of throttle right before I shut it down it would be a little easier to start. And it was fouling plugs very easily. I'm thinking it may be a needle and seat going bad or it could just be the quickly fouling plugs. I'm going to try cleaning the carb up a little today

 

[mikidymac]

Wait, so you have done all this work and never rebuilt the carbs?
Step 1. Rebuild the carbs with new Genuine Mikuni parts.

 

[Cheflen]

Carbs have been gone through not too long ago. I've owned this ski and had everything running perfect before the crank siezed. I left the carbs exactly as I had them before it was running. That's why I didn't think they would go bad within a few months. Considering it was running perfectly fine about a month ago

 

[mikidymac]

Ok, I didn't know that.

 

[Cheflen]

Do you think this would still be a carb issue with the constant fouling of plugs and sometimes hard starting? Does it makes sense that the carb can go bad after sitting for a month or so? I know I messed with the low speed adjustment screw a lot probably too much but I put it back to spec and it's at stock setting now. Or would the excessive oil make it slightly harder to start

 

[mikidymac]

Where are you getting the excessive oil?
It should not be fouling plugs at all.

 

[Cheflen]

I put oil in the gas along with oil injection for the break in period

 

[mikidymac]

How much oil in the gas? It only needs 50:1 premix with the oil injection too.

 

[Cheflen]

It had about 2/3 of a tank and I put a half a quart of oil in so I'm not sure the mix it's a 2001 gti

 

[greenhornet2]

I'm not a 2 stroke guru but sounds like you are running too much oil in the gas and it maybe running rich on top of that.

 

[Cheflen]

I'm not a 2 stroke guru but sounds like you are running too much oil in the gas and it maybe running rich on top of that.

That's exactly what I'm thinking. I think it's too much oil but I'm not sure how it's running rich on top of that with the stock carb adjustments, I don't really want to bring the low speed screw in much more but I'll have to try that

 

[Cheflen]

Should I try switching to a BR7ES plug to burn the oil a little hotter? Just so it can burn it a little instead of fouling it out

 

[mikidymac]

No, the plugs are not your problem. If your ski doesn't run on the stock carb settings you have something wrong.

Either too much fuel or too much oil is fouling the plugs

 

[Cheflen]

No, the plugs are not your problem. If your ski doesn't run on the stock carb settings you have something wrong.

Either too much fuel or too much oil is fouling the plugs

Well considering it ran good with the same carb settings before I'll hope it's the oil, I'll just keep a lot of spare plugs and run out this tank for the break in

 

[Mekanix]

So what are the compression numbers now that you've ran it ??
If your still at around 138-140.
There IS your problem!
155 perfect
150 normal
145 plan on rebuilding soon
140 and below, melted piston crown, missing top ring land. Anything that says your screwed and need to do a top end properly.

Guys here have been asking for those numbers as that first and foremost is the "well it runs on the trailer but not in the water "culprit.

Then if the engine is healthy its carb related. After that you can get really picky.

Too much oil will do weird things but it will still run and smoke.

Being Rich on oil in the mix means your going to be lean on the fuel side for the same volume of fluid coming out of that carb.

 

[Cheflen]

So what are the compression numbers now that you've ran it ??
If your still at around 138-140.
There IS your problem!
155 perfect
150 normal
145 plan on rebuilding soon
140 and below, melted piston crown, missing top ring land. Anything that says your screwed and need to do a top end properly.

Guys here have been asking for those numbers as that first and foremost is the "well it runs on the trailer but not in the water "culprit.

Then if 5he engine is healthy its carb related. After that you can get really picky.

Too much oil will do weird things but it will still run and smoke.

Being Rich on oil in the mix means your going to be lean on the fuel side for the same volume of fluid coming out of that carb.

Well the engine is good. I think my needle and seat has started leaking as this is now a starting issue. First start of the day I can run it however long I want as fast as I want, but as soon as I kill it it doesn't want to start back up. I also noticed if I kill it RIGHT AFTER giving a lot of throttle it'll start back up so there is fuel leaking in. I'm going to probably have to do another carb rebuild as I rebuilt it last year

 

[Cheflen]

So what are the compression numbers now that you've ran it ??
If your still at around 138-140.
There IS your problem!
155 perfect
150 normal
145 plan on rebuilding soon
140 and below, melted piston crown, missing top ring land. Anything that says your screwed and need to do a top end properly.

Guys here have been asking for those numbers as that first and foremost is the "well it runs on the trailer but not in the water "culprit.

Then if 5he engine is healthy its carb related. After that you can get really picky.

Too much oil will do weird things but it will still run and smoke.

Being Rich on oil in the mix means your going to be lean on the fuel side for the same volume of fluid coming out of that carb.

Also those compression numbers were with a cold motor that hasn't broken in and I forgot to open the throttle during the test so that was a closed throttle test

 

[mikidymac]

So what are the compression numbers now that you've ran it ??
If your still at around 138-140.
There IS your problem!
155 perfect
150 normal
145 plan on rebuilding soon
140 and below, melted piston crown, missing top ring land. Anything that says your screwed and need to do a top end properly.

Guys here have been asking for those numbers as that first and foremost is the "well it runs on the trailer but not in the water "culprit.

Then if 5he engine is healthy its carb related. After that you can get really picky.

Too much oil will do weird things but it will still run and smoke.

Being Rich on oil in the mix means your going to be lean on the fuel side for the same volume of fluid coming out of that carb.

150 psi is perfect compression and 120 psi and below is time for a rebuild. 140-145 is perfectly fine.

 

[Cheflen]

150 psi is perfect compression and 120 psi and below is time for a rebuild. 140-145 is perfectly fine.

Yeah the motor runs good, I just tore the carbs apart yesterday and the needle and seat were very corroded for some reason so I rebuilt the carb and put a new needle and seat in and hopefully water testing today and I'll get back with results.

 

[Cheflen]

So I rebuilt the carb but I didn't have anything to test the pop off pressure. I took it to water test it. Tried starting it on the trailer multiple times, it started up right away each time so I started pulling it out, ran good for a 20 minute run then I shut it off and had someone else ride with me and it wouldn't start up so I tried it alone again, took a lot of cranks I had to give it a lot of throttle and try choke and it finally started up again, ran great until I shut it off and then it didn't want to start. I kept the same spring but had a new needle and seat and replaced the arm that attatches the spring and needle. I think I need to go back to the original arm and see if that is adjusted to the proper pop off since I don't have a pop off tester and see if it runs better with that.
These were all genuine mikuni rebuild kits and needle and seat.