Re: 98 180 WOT RPMs, Speed
 

Brewfixer what RPM's are you getting at WOT?

Re: 98 180 WOT RPMs, Speed
 

well got it on the water today and all is well. 44mph at 4600 rpm. amazing what a dead cylinder with do. the loss in of the last couple of mph im sure is due to the older gas i still have in the tank.

ran pretty hard today (3 hrs) and burnt maybe a 1/8-1/4 tank. whats the normal burn rate?

Re: 98 180 WOT RPMs, Speed
 

Good to hear you solved your speed issue. I also managed to figure mine out... Seems I was a little conservitive on the trim so i trimmed way up and finally got my boat to hit 54 mph on speedometer @ 4400 rpm's / ~51.3 on GPS. However, umong a few issues i noted... The speedometer does not start working until i almost hit 30 mph. Does anyone know if this would be an indication that it will need replacement or rebuilt? out of the water the paddle wheel does spin freely.

Re: 98 180 WOT RPMs, Speed
 

Good to hear you both have solved the issues, now I have similar to same. I just got her out this weekend and couldn't get the rpm's above 3800 and speed of 42! Just had my SS 21P rebuilt and is perfect, just put half tank fresh fuel in, trimmed it to the point where it would start to porpoise a bit, which was not very much at all.

I was wondering Brewfixer, how much would you bring the trim up? Maybe I am just not adjusting correctly?

And I only had 2 adults and a kid. I am wondering if the fuel we are using is just poor this year, there sure are alot of posts with this same issue. Although you both found actual solution other than that, so not real sure, but I was dissapointed that my buddies Blue Water, with a 5.0, beat me out there today.

Re: 98 180 WOT RPMs, Speed
 

Darn I didn't take a photo of the trim meter but it was just on the high side of the mid point.

Re: 98 180 WOT RPMs, Speed
 

Same boat, similar issue. I have a '98 180 with 4.3 merc. I had to get the Faria tach replaced on warranty beginning of season. The tach seems to read fine low end, but it is either reading low on the top end (WOT around 3800) or I am having an issue. I took a look at the prop yesterday and no identifiers of pitch, but when I purchased in March believe I recall the prior owner had a 23P and I have not changed. As seen above plug/wire issue could be causing loss of one cylinder, but I have a hard time believing that is the case as the boat idles steady and runs smooth. I know some tachs have 4/6/8 cylinder settings and have not had the opportunity to investigate if mine is incorrect. Does anyone know if the Faria's have these settings? Any other thoughts? I know WOT RPM will be lower with 23P, but 3800 seems too low.

I need to get a GPS speed. Based on my prior 20" Chaparral with 4.3 this boat gets up on plane as quick or quicker.

Re: 98 180 WOT RPMs, Speed
 

Duke:

Yes, the Faria tach has a dial on the back that can be set to 4 - 6 - 8cyl. I would suggest spinning it a couple of times before dialing in to the correct setting.

A 21" pitch should run around 4300-4400rpms at WOT so a 23" could be down as low as 3800-4000. I only know one other person on this site that can run a 23" prop on a 4.3L - 180 where most of us run 19" 3 blade or 20" 4 blade props on similar boats.

Brewfixer: You could have a little bit of crud in the speedo line or it might be slightly pinched somewhere. That would cause it to not kick in until there is a bit of pressure built up.

Re: 98 180 WOT RPMs, Speed
 

Mikey, how would one go about cleaning up crud in the speedo line?

Re: 98 180 WOT RPMs, Speed
 

Compressed air after disconnecting the line at both ends.