98 speedster issue

[mtrainer]

Ok so I am out of ideas on this one. I have a 98 speedster, the twin with 220 hp. I have had all kinds of problems with this boat and now I have a new one I cant figure out.
On my RH engine, the Aft cylinder is dead. I can pull the spark plug lead off of it and it will keep running, if I pull the plug of the fwd cylinder it dies right away. I am getting spark and have good compression.
I ended up changing the engine last summer after a bearing in the crank went bad and busted through the lower case. This season I put a new carb on the aft (PTO) cylinder since my old one had a broken screw (I am trying to sell the boat and didn't want the new owner to have any surprises such as the temp weld job holding the needle valve retainer down. Hey it worked all last season). So it has a new carb and the jetting is the same. When I took it out for the first time the season it ran fine for the first 10 minutes then I lost power in that engine. I am unsure if it went into safety mode or was just running on one cylinder.
Anyways, I am thinking it is kind of unlikely that it is the engine or the carb but who knows at this point.
Has anyone ever heard of a fuel pump being weak and only pumping enough gas to the fwd carb and not getting any to the 2nd one?

 

[mtrainer]

Well swapping fuel pumps side to side was no help

 

[Coastiejoe]

You say "GOOD COMPRESSION" what is the number?

 

[mtrainer]

You say "GOOD COMPRESSION" what is the number?

150 on the cylinder in question

 

[Waterluvr]

You say "GOOD COMPRESSION" what is the number?

And you're using an ignition tester rated for a CDI ignition and the boat has the correct plugs marked R for resistance rating? Seen boats come in with the same plug number, only one of them marked (R) running on one cylinder on Nippondenso ignitions.

Given those first two variables are within spec. for compression and ignition you're only left with a fuel issue and that's easy to check. Start by verifying fuel delivery from the shut off valve with a Mity Vac or similar device with an inline recovery cannister. You want to check the main on setting for proper fuel flow, then the reserve and off should shut the flow down.

If that checks out pull the pump and carbs, pull the small basket filter for inspection and clean them and check metering arm height and pop off pressure and use new kits if needed.

By the way, what color are the fuel lines in your boat? If grey, you still have a built in issue from the factory from the defective Tempo brand fuel lines.

Pic from a recent thread this past week showing the issue of the green slime from the lining deteriorating inside the hose that plugs everything up.

 

[Coastiejoe]

If you put a small amount of pre-mix into the carb does the cylinder fire up then?

 

[mtrainer]

And you're using an ignition tester rated for a CDI ignition and the boat has the correct plugs marked R for resistance rating? Seen boats come in with the same plug number, only one of them marked (R) running on one cylinder on Nippondenso ignitions.

Given those first two variables are within spec. for compression and ignition you're only left with a fuel issue and that's easy to check. Start by verifying fuel delivery from the shut off valve with a Mity Vac or similar device with an inline recovery cannister. You want to check the main on setting for proper fuel flow, then the reserve and off should shut the flow down.

If that checks out pull the pump and carbs, pull the small basket filter for inspection and clean them and check metering arm height and pop off pressure and use new kits if needed.

By the way, what color are the fuel lines in your boat? If grey, you still have a built in issue from the factory from the defective Tempo brand fuel lines.

Pic from a recent thread this past week showing the issue of the green slime from the lining deteriorating inside the hose that plugs everything up.
View attachment 26980

I will have to check for the R. I think I am going to throw new plugs at it anyways, I don't think it will do anything since I have swapped them fwd and aft with no effect.
I don't actually have an ignition tester, I will have to see if I can find one. All I did was pull the plug and verify I was getting a spark.

My boat doesn't have a fuel selector valve but I don't think that would be the problem either way since the fwd carb is getting fuel. Also I did notice that when I move the accelerator lever it does squirt fuel into it. But I think that is run off a separate line than the main fuel to the carb so I guess that doesn't really mean anything

I have no grey lines, they are all black.

I have pulled the pump apart and everything looks fine. Since there was nothing wrong with it I took the pump off the LH engine (which has had no issues) and installed it on the RH engine. It didn't fix anything.

I checked the new carb for the jetting before I put it on and it was perfectly clean. I guess my next thing is going to pull the carb and make sure it didn't get any crap in it. If I don't find anything wrong with it I will swap carbs from the LH engine and that will pretty much rule out the fuel system if it doesn't fix anything.

 

[mtrainer]

If you put a small amount of pre-mix into the carb does the cylinder fire up then?

I actuated the accelerator pump lever and didn't really notice any difference.

 

[Waterluvr]

I actuated the accelerator pump lever and didn't really notice any difference.

And you really should have seen an immediate correction in that cylinder with the accelerator pump hitting it with squirts of fuel.

I use a Stevens Instrument marine CDI ignition tester, it finds all sorts of issues with ignitions that still fire a visible spark over a plug electrode gap that's not enough to ignite the cylinders compressed fuel/air mixture. It will allow you to see each individual wire and cap are sending a healthy secondary impulse from the coils through to the plug.

Your ignition wire set uses resistor caps that just thread on and off the bare wire end, clip the tie and back the cap off the wire and snip off 1/4" of the bare wire and and thread the cap back on and tie it in place and see if the issue goes away.

It's a common issue on CDI ignitions to lose part of the secondary pulse at the wire end and cap connection.

 

[Coastiejoe]

I'm confused... You say you have 150 psi, spark and fuel. It HAS to run.

Try putting premix into the carb so that you KNOW there is fuel in there. We need to know things, not assume things.
Correct plugs are plugs are important. Resister plugs in a non-resister spark system for example will cause issues.

 

[racerxxx]

If it hasn't been said yet, just swap the lead on the front to rear spark plug. See if it runs on the rear cylinder. Literally just plug it on the pto spark plug and try it.

It's a dual engine, you have the parts right next door to swap.

You also have to verify your getting gas to the pto carb.

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[mtrainer]

Your ignition wire set uses resistor caps that just thread on and off the bare wire end, clip the tie and back the cap off the wire and snip off 1/4" of the bare wire and and thread the cap back on and tie it in place and see if the issue goes away.

Ok I replaced the plugs and redid the lead. Not that it means much but the spark looked a lot stronger. It still idles at 1/2 the RPM of the other engine. It will go to full RPMs but its on land and there is no load on it, so I really wont know if it fixed it until I get it in the water.

 

[mtrainer]

If it hasn't been said yet, just swap the lead on the front to rear spark plug. See if it runs on the rear cylinder. Literally just plug it on the pto spark plug and try it.

It's a dual engine, you have the parts right next door to swap.

You also have to verify your getting gas to the pto carb.

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Will that really work? I know I have had the leads swapped before and it didn't run to hot at all. Wouldn't the timing be 180 off?

 

[Waterluvr]

Ok I replaced the plugs and redid the lead. Not that it means much but the spark looked a lot stronger. It still idles at 1/2 the RPM of the other engine. It will go to full RPMs but its on land and there is no load on it, so I really wont know if it fixed it until I get it in the water.

It looked a lot stronger because it was. Might as well do the same to the adjoining wire and boot and go try it out after adjusting idle speed. You should be able to noticeably change the cadence of the motor now by pulling either of the plug boots while it's running.

 

[racerxxx]

I almost positive on the older skis you could, but with the big mpem in the boats you might not be able to. Just as long as you tried.

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