Not Enough Air to Motor

[Jasfarrar]

I have a 2000 Tige 21i and having an issue. Runs perfect for over an hour, then it starts to spit and sputter like its starving for gas. Fuel pressure is good and its not overheating. After some trouble shooting, I finally realized it is not getting enough air and its starving for air. When I open my engine cover to get some air in and hit the gas again it clears up and runs perfect again in seconds. I cut some vents in the front of the engine cover thinking it would help and it did go a little longer this past weekend until it did it again. Anyone have any other ideas on how to solve this issue? Maybe cut another vent in the back on the engine cover to let the air pass all the way thru. Why is there not vents originally in this boat. BTW, the lake I take it in is extremely warm.



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[lalijaca]

I have a 2007 21i, but fitted with a MP 340HP. I don't have this problem, but my previous boats did. Can I suggest an air scop in front of the windscreen that directs air via ductwork to the engine when at speed. This will force feed air in their and push any hot air out the back. When sitting still, a blower could keep an in rush of fresh air coming.

[Ewok]

Does the boat not have a blower? You should keep the blower running the whole time the engine is running, that could help a bit.

[Ruger761]

What motor do you have? Carb, EFI, MPI? You might check that the air intakes infront of the windshield are clear so air can get down to the motor and check your blower like Ewok said. Check the ducting that is going from the vents to the bilge and from the blower to the exit vents under the rear locker door. Those ducts are easily smashed or cut. Is your flame arrestor dirty/clogged? You shouldnt be having that kind of issue. We run in 100+ air temps with 90+ water temps all the time during the summer.

[Joeprunc]

X2 on what Ruger said...check your ducting.

[hopps1945]

Not to hijack a thread but had this issue last night. I have a V-drive with the MPI motor (2000 2300V Limited) We had been sitting anchored for about 30-45 mins. Went to start up and it spitted and sputtered and died. Did this a few more times. Hit the blower, opened up the compartments and let it sit a few. Thought I might have smelled a faint odor of gas. Tried it again and it finally started. Wasn't warm, air temp was around 80 so not like the blistering hot days we had a week or so again.

[hopps1945]

Just read the service bulletin listed in this thread:

http://www.tigeowners.com/forum/show...ould-not-start

Some great information and a few things on mine I need to check.

[Ruger761]

Hopps your issue sounds more fuel related. Weither thats vapor locking, bad fuel, fuel pressure vs an air problem. Knock on some wood but so far this year after adding my second fuel pump (like bulletin said) I have yet to have any vapor locking issues. Granted it just now hit the high 90s and 100s temps out. But no issue so far.

[hopps1945]

It's funny. Seems like a fix one problem only to have another. Prior to this, one of the engine compartment hatches was off to get repair work done and we also had a small water leak so we always had water in the bottom of the hull (which the fuel line from the tank was always sitting in. We got the hatch back and within a week, got the leak fixed. This was our second time out since then. Also, this is our second tank of fuel since we had it out of storage. I did not add anything to it the last time. Maybe I should start too? Once the compartment was left open for a few minutes, no problems starting it so I am leaning towards a possible vapor lock issue. Also, I have not replaced my fuel filter yet this year (sitting on shelf) so I need to take care of that also.

[Ruger761]

Id start by changing filter, and fresh tank of non ethonal if you can find it. And a can of Sea Foam never hurts. See what that does. If it does it again then start looking at other areas. But that does make an interesting point of fixing the water leak, which cooled the line, could have been whats causing your issue now.

[hopps1945]

Funny how it snowballs... Good luck on no ethonal around here but will look. Thanks for the info Ruger. I will report back.

Sorry Jasfarrar, didn't mean to hijack but figured since we had some of the same issues we both could learn from all the great people on here together!

[Ruger761]

That it does. Station down the road has me spoiled. They have reg 10% and no ethanol on every pump now. $0.20 diff in price

[hopps1945]

So was out most of the day today with a few stops ranging around 30-40 mins. No problems at all. We did replace the fuel/water separator filter and filled up the tank though I forgot to add the Sea Foam this round. When I was changing the fuel filter, I noticed one of the lines coming off the bottom of the exhaust manifold that runs up to the thermostat housing was sitting right on top of the fuel filter housing. I know that hose can get hot so maybe that was one of the issues, I don't know. Either way, we had a good boating day without any issues. Pretty happy!

[Ruger761]

Good to hear, thanks for reporting back.

[Jasfarrar]

I had the same issue this weekend. The vents below the windshield were broke and I fixed them. Ran the blower the whole time, Fuel pressure never drops when it starts to sputter, and temp gauge never goes up. Any other ideas? Someone said a Coil? Seen some other threads about a distributor cap? The boat would run fine if I left the engine cover propped open, which I did for the rest of the day. This is so aggravating. Hope someone can help!!