Compression test?
 

We'll as the title says I had to do my first compression test, today. I warmed up,the engine, disconnected the coil, but I didn't keep,the choke open will,this change the readings? My numbers didn't come back all that great the worst was 105 best 115, now shouldn't a good reading be about 150. This all started at the beginning of the season, boat didn't idle right last top end rpms. I put new cap, rotor and new plugs. When I changed the plugs number 4 plug was bad totally fouled I guess I was running on 7. After that boat ran great, until that same plug fouled out again. Along with that I started to notice I was using a lot more oil I run Mobil 1 15w50 synthetic.
I have already talked to the shop I have dealt with for over 20 years about this and showed him a couple of the plugs, and he said with a smile this doesn't look good. After talking for a bit about different problems this could be I asked what a total rebuild would cost he said about 5k with them taking it out and back in.
The engine was a remained gen IV 454. I have read many other post over the years guess I didn't think this would be my engine. Any thing you have to say good or bad I would like to hear it, I just want the boat ready in the spring

Thanks

Mark

Open throttle would maybe change only 5 on reading... Of course what you don t want is having 45 pounds different from one to the other! Seems like it is not your problem! BUT !

They are low... Since you say its burning much more oil, looks like its time for a rebuild. You could always take a leak down test, this would tell you more where is the problem for low compression. But burning oil tells me cylinder and rings!

Keep us posted!

I was thinking rebuild also, I guess this boating.

with compression being that low and useing oil i would say tired rings,valves not sealing well and valve springs weak.afraid it is time for a rebuild.

How is the compression on #4 vs the others? From your description I was leaning towards number 4 is sucking oil through the intake gasket, from the lifter valley. If it runs good until the #4 plug fouls I would look at the intake gaskets and even the intake itself for a crack.

Well I also forgot to tell you when I was ready to take it out of the water the last time I did notice a couple of small water droplet around the top of the intake not a lot no water in the oil.
I know most of you have more engine experience than I do, if I do a rebuild having my shop do it just keeping it stock does 5 k sound right or is this low.

If you decide to rebuild and are budget minded you might think about one of the head sets for sale in swap shop section. 1 set is oval port 279 heads, that will give you a little higher compression with fresh rebuilt. The other set is 088 rectangular port with 150 hours includes roller rockers. Either of these should save you a bunch of money. I wish these were available 2-3 months ago.
Just thinking out loud.

I would love to throw more power in the boat but I only have the alpha. So I think 350hp would be it.

Same problem with my '87 242. No hole shots and easy on acceleration. I added power this summer and my short term solution is keep a spare alpha drive in suburban, cheap insurance. Longer term solution is bravo conversion when i put real hp to boat. Good deal on new bravo hp complete transom set-up in swap shop $1,500 (i think). Just add an outdrive and you are set for adding substancial hp.
Good luck and keep us posted.

Did you repower or rebuild and hp did you end up with? I have over 300 hours with this alpha and no problems.