i have a 2001 929cdx with mercury 225 efi. In the fall I would get on plane quick and hit 71gps/mph. Before putting the boat in the water after winter I had the prop balanced at a local propeller shop. Tempest Plus 25p. Now it takes about 15sec to get on plane and I can only hit 60-65mph.
Any thoughts? I changed the water/fuel separator. Could they have messed up my prop?
Yes they could. It could also be spark plugs after a long layover. Could also be fuel-related. How did the VST filter look? Your boat is old enough it might also have the pre-ethanol fuel lines and they could be coming apart internally and introducing trash or blockages.
2008 Bass Cat Pantera Classic
2014 Mercury Pro XS 200
I haven't looked at the vst filter. (Didn't know it existed till I read your response). The plugs all look the same. They were new in October. The other thing going on is it pops at idle speed. I was told this is a lean condition.
Wait. Do you have a water fuel separator in the bilge area? When the opti's came along, mercury recommended that any fuel/water separator outside the motor be removed, they could cause fuel restrictions. Since you just replaced yours, that's a point of suspicion. You could bypass this for a test with a double barb connector. That would tell you whether the new separator filter is bogus or not.
2008 Bass Cat Pantera Classic
2014 Mercury Pro XS 200
No it's under the cowl. Screw on filter.
Well u need to eliminate the obvious. Try a different prop.
Bryan McDonough
2023 Nitro Z21 XL
Nitro Team
I should also mention, after changing the filter and running seafoam through it and the fuel tank, I was able re get on plane quick but still wasn't getting to full top speed (67 instead of 71). This was the case for 2 trips last of which was Saturday. That morning it was perfect for the first run. Got up quick and hit mid 60's. The rest of the day it was a dog. 10+ seconds to get on plane, struggled to get over 60mph. Rpm seem fine. 3500ish at takeoff and 6000ish at wot. I called the prop place. They said there's essentially no way the work they did would effect top speed. They offered to look at it if I get it on a dyno to diagnose any mechanical/fuel issues.
I would look at having your injectors cleaned ad adjusted, I had the same problem and sent my injectors out to get clean and properly adjusted. It did the trick, just saying!!!
Do I have 2 electric fuel pumps? I know there's one in the VST. Is there a low pressure pump somewhere?
So your still able to obtain full RPMs and not getting speed later in the day?
Bryan McDonough
2023 Nitro Z21 XL
Nitro Team
Sounds like prop, If you can hit 6K!!Originally Posted by danhrph
And the last statement I would be a little PO'ed. If you get the engine dyno'ed..
I would send it to Croxton or one of the guys on here, be done with it. Or get a new prop.
The only thing that changed was the prop was messed with,,,I say KISS applies to this situation,,IMO...I would not touch the engine until you have another prop to try.
I agree. I'm kinda wondering if the prop had previously been adjusted to 26p. I bought it used so I don't know. If the shop put it back to factory specs that would explain the loss of top end speed.
I think ill buy a 27 tempest and sell the 25. Mercury says max rpm is 5800 but I'm hitting 6200
Keep it simple:
It worked good in the fall, so what was changed, and what could happen over the winter?
1. The prop was worked.
2. The layover in the winter can cause fuel to break down, which can plug filters and injectors.
Update: I got a 26P Tempest Plus and I now hit 66mph. However, I noticed something the other day. When I'm on plane and trim up I used to hit a point where the water pressure alarm would go off. Now I do not. The trim and tilt work fine at idle but don't seem to be working on plane. Is this a sign of a hydraulic leak maybe?
Every prop will require a height adjustment
Is the holeshot better?
Yeah I forgot to mention that. Holeshot is fine now.
2006 Ranger Z21 w/Yamaha HPDI 250 VMax
So the prop man wrecked your prop.
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