Can a kicker actually slow it down that much?

[Lundexp]

Thanks guys for sticking with me while I try to figure this out while I probably have been stubborn believing the engine is at 100%. Just trying to cross out the other options first before having to take it to a certified yamaha dealer/ mechanic over a hour away as I've always done the mechanics myself on my previous boats.

Took it out again sunday with a operator I trusted this time and had him run it to WOT while I looked out the back and couldn't even see the plate it was well below the water even at full trim. So I raised it up one hole last night, it's now at 2nd hole up. Hopefully I can take it out again soon to see how much the rpms come up. If the plate is at or above the water at this new hole setting and the rpms are not up enough I will have to admit defeat and take it to a dealer to have the motor checked out.

Looked at the prop and it does have that sharp lip along the back so it may not have been reworked. It does still scratch my suspicion that the locking tab wasn't bent down and there wasn't a cotter pin and the nut wasn't that tight. All the while it was sitting next to 3 other boats running yammies with Tempests too. . UMMMM. Maybe it's just a coindeince.

Thanks again guys

[Robert M]

Did you pull the plugs and look at them.Pretty easy way to tell if its hitting on all 4.Also check for loose plug wires or any damage to plugs.

[Lundexp]

Yes I did pull all the plugs. The top 3 were half brownish and other half whitelike with the 4th, bottom cylinder half blackish and half whitish so i'm keeping my eye on that one cylinder. I got all the paperwork with the boat and one indicated that the dealer replaced the plugs last october but there's no way they did because the posts were all scratched up from pulling the wires and etc and even the outside white part was filthy as like it was never replaced. Swapped out the plugs with the ones I pulled out my last F80 as I change them every year and are the same ones and they were clean white and it still runs well and gets the same rpms. I will see how much my rpms come up after I take it out again since I raised it a hole. If not much then I will have to do a compression test to see if there's a variation and go from there

[Robert M]

I bought a 2006 1800 explorer with a 115 on it about 6 weeks ago and just pulled the plugs last night and they all looked identical and the guy told me they were never changed.My boat also isnt up to speed yet as it came with a 15 prop on it and last time I took it out I checked the cavitation plate and it was well under water.So today the motor is getting raised up at least one hole (it is in the top one now) and is getting a 17 stainless prop.Right now it runs a good RPM but it is slow and I can feel a drag.Right now it runs in the mid to upper 30s and should run in the mid 40s with an average load.I can see one of these running close to 50 with a 150 on it but mid 50s I think is a strech unless its being towed.

If I were you I would put a new set of plugs in your motor and some sea foam or injector cleaner and run it a little while and then check the plugs again.If they dont look the same you might have other issues like a sticky injector etc.

Ill let you know how mine pans out.

[Lundexp]

Robert M, glad you found a 1800 after I snagged this one up. Raised it up a hole, at second hole up now and can see the plate now so is where it is supposed to be. When I first got out I got it up to 5600 RPM and 47mph compared to the previous 5300 at 44mph. But at the end of the day after a daylong of being shut off and trolling with the T8 it wouldn't do any more than 44 mph again. Guess I'm going to have to take it to a dealer to have it scanned. Probably is just a dirty injector.

I'm not concerned about top mph, 50 would be nice but not necessary, just want to get my motor up in the optimum upper operating range so it can wind up easily and not have to struggle when rough weather comes up..

When I bought my last 2002 1800 with a F80 it came with a 15 pitch, it struggled to hit 5000 rpm as that's a small motor for a big heavy boat. I ended up repropping it to a 14 and raised the motor a hole to second hole from bottom and got it up to 5600-5700 and could do 32mph on a good day

Around 17P does sound right on your F115 and wouldn't be suprised if you find your optimium motor setting at the second hole up from bottom too.

[Robert M]

Finally got the boat out yesterday and still cant see the cav plate when running.Still an inch or more under water trimmed up.So Ill raise it one more hole 3rd from the top and try it again.Gained a couple MPH but lost about 600 or so RPM with the 17 stainless prop.

[Lundexp]

I had a feeling 3rd hole from top probably would be the right setting for you too. Once you raise it a hole you should get about 200rpm back hopefully. By the way, the stainless prop has alot more grab and won't slip as much as the alum prop so the rpms may be lower now than expected, at least i'm assuming the 15 was alum. What RPMS are you getting by the way?

[Robert M]

Right now with the SS its running about 5200 RPM trimmed up.

[Robert M]

Raised the motor up one more hole to the third hole down and will give it a try next weekend.Cav plate is now about 1+ inch above the bottom of boat.Hopefully that will work.If not Im getting very good and fast at moving the motor around.Will report back with results.