29 Scarab Question

[Karaokemike]

Friend has a 29 Scarab with twin small blocks. Two years ago the boat had a very bad miss and she took it to a local mechanic to find that both engines had sucked water into them and lost a couple cylinders on each engine.
The cause of the problems was found to be that the flappers had gotten blown out of the tips and sucked water back into the engine. Two engines later and flappers reaplaced problem solved. This all happened mid summer.
That winter it happened again but was caught in time to prevent any damamge.
This year she called to have the boat pulled out and the mechanic noticed the boat had a miss again. He did a leak down check and there were two bad cynliders again on the port engine. Luckly this time a head job fixed the problem but the cause was no flappers again!!
Art Lilly has the boat now and told me that he is going to replace the tips with a different style to take care of the problem.


Has anyone else with a 29 Scarab had this problem before?
What did it take to fix it.

Any help would be great.

Thanks!

[Pat McPherson]

It sounds like there may not be enough down angle from the exhaust riser to the thru hull exhaust tip. If possible, I would add a 3"spacer between the exhaust manifold and the riser.
A 29' Scarab twin sits real low and could get water up the exhaust pipes easily while the boat is in the water and not running or from running in reverse at an idle.
If the tips are changed, get a set that has internal flappers and will also except external flappers.

[Karaokemike]

Hey Pat thanks for the response. The riser idea has been talked about but there is so little engine clearence that the hatch would have to be changed to make it work. The boat does have external flappers but just dont this its enough.

[White Knuckles]

I have a 29 Scarab that has both internal and external flappers. It's kinda funny because I had it in the shop to replace a water pump, and the mechanic called me and said that he was scared to start it because it was knocking, and it may cause real damage. I laughed and told him to stick a screwdriver to his ear and the exhaust riser, and sure enough, it was the internal flappers that he was talking about making the noise. lol