Propeller issues > figure this one out

[captmatt3311]

Hey all ! So I got the motor swap complete on my 1998 ranger commanche 18svs. I removed a 1998 mercury 175 efi and replaced it with a 2001 mercury 200 efi. (2.5l). I put a brand new SEI lower unit on it. Geared in 1.87. I was running a bobs nosecone. Now I am NOT. I put the same prop as I had on the 175...... a 25p tempest plus 3 blade.

Took it it out for my break in period etc etc etc . Now it's time to raise rpm and get on slow cruise. ......... BUT I have to put the hotfoot to the floor to get it up on pad and it has the worst hole shot. Once up on pad ... rpm are available. As in I can raise rpm normally. Do I need to drop a pitch size and go with a 24 ???? And why...... did the bobs really make that big of a difference ????

thanks for all the helps guys . Much appreciated as always !
matt

[Merc 200]

I had a 2003 200 EFI on a Stratos 195 Pro XL. It had a 25p Tempest the old kind before the vent plugs. The prop cracked. Put a 25p new Tempest with the vent plugs. Tried various plugs. i could not get the boat on plan with 2 people and live wells full without the other person laying on the front deck. Raised the motor and that helped some. I finally put a 24p on it had to watch the rpms but it would get up on plane and ran great

[John Jackson]

Port timing on the 200 makes less bottom end torque for holeshot than a 175. You might just need to vent the prop a little more. (And keep an eye on the SEI lower as many of them fail in a short time)

[JR19]

Change your vent plug configuration. If the prop is struggling to build rpm on hole-shot open the holes. This will create more ventilation and allow it to build rpm. If it spins up too fast and does not want to bite you have too much venting and need to close the holes. The make solid plugs, large plugs and small plugs. I have a totally different set-up but I run one hole completely open and two holes with large plugs...you just have to figure out what ventilation your set up likes.

Another thing to check is your prop to pad height...around 3.5" should be a good starting point...higher = easier to spin on hole-shot and lower = harder to spin. Just be careful because to high and too low will cause other problems such as chine-walk, too many wide open throttle rpm's due to slip and low water pressure if going to high. For your style of boat 3.5" will be close. Getting the motor height right can sometimes be very sensitive. 1/4" up or down can sometime make a noticeable difference. You just have to find the sweet spot. I would figure out my prop venting before I played with motor height unless you are very deep like 4" or more.

[alli ss]

If you were running a low water pickup nosecone and had the motor raised and you put the new motor with the sei in the same spot youre probably gonna have to drop it another 2" just to get water pressure- maybe more. You definitely dont need a nosecone on a ranger so just drop the sei down at a normal prop to pad height and start over on your setup. Until you do youre running the risk of melting the new motor down. Some of the ranger setup guys can help you with a good measurement according to your boat and jackplate

[captmatt3311]

So here's the update guys.
i measured my prop to pad distance and got 4.25 inches ....... which theoretically should be enough ...more than enough.....too much p2p distance ....... new water pressure gauge installed. New thermostats installed......... no results. The engine runs much better now as well..... getting up on plane as normal with 2 vent plugs removed and 1 remaining . Overall issue here now is that the running temp is too high. I'm idling at 135-140 but once on plane after 1-3 minutes I'm right up to 160-170 degrees . In the past I've always been able to run at 145 or less . Conditions dependent . That is with the nosecone , 175 efi, same prop 25p tempest plus . What to do ?

[captmatt3311]

Only thing I can think is to put old lower unit back on reluctantly and see what happens then .......

[Charles Prestridge]

Where are you measuring engine temperature?

Does the Mercury EFI give you this informtion?

[captmatt3311]

Engine temp is coming from dash gauge which is connected to sensor on port head next to thermostat

[alli ss]

I think your gauge is wrong if youre idling at 135-140 and not getting an alarm when it goes past that